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On the afternoon of August 24, 1914, the German warship Magdeburg steamed out of the East Prussian harbor of Memel toward the most fateful accident in the history of cryptography.

A four-stacker, the Magdeburg was what the Germans called a small cruiser, different from the larger light cruisers. She was new (three years old), well-armed (12 fast-firing, 4-inch guns), fast (27.6 knots)–and unlucky. Her acceptance test had not gone well. Her commissioning had been delayed several months. She had never participated, as was intended, in the autumn 1912 naval maneuvers. Some equipment was still not in order when she was declared “ready for war” and when the ancient city of Magdeburg, for which she was named, sponsored her in two days of festivities. One of her turbines gave trouble. And unlike her sister ships, which got assignments suitable for cruisers, the Magdeburg merely fired test torpedoes.

The Magdeburg was part of  Germany’s Baltic Fleet. When war with Russia, France, and England broke out in August 1914, she dropped her test assignment and undertook more typical cruiser tasks. These were directed against the Russians, whose empire included Finland, Estonia, Latvia, and Lithuania–the countries bordering the eastern Baltic. In her first operation, the Magdeburg and another small cruiser, the Augsburg, arrived off Liepaja, Latvia’s naval port, to lay mines. They gained an unexpected success: The Russians, thinking the appearance of the two ships portended a major fleet operation, blew up their own ammunition and coal dumps and scuttled ships in the harbor entrances. In the two ships’ second and third operations, they shot up some lighthouses and a signal station and laid a minefield not far from the mouth of the eastern arm of the Baltic Sea, the Gulf of Finland, at whose farther end lay the Russian capital, St. Petersburg.

A few days later, on August 23, the commander of a new flotilla ordered his vessels, which included the two cruisers, to assemble for an operation. The Magdeburg, in Danzig, then a German port, went first to Memel, at the extreme east of Prussia, for some gunnery exercises to reassure the population, nervous because the Russian border was not far from the city limits. The next afternoon the warship set out for the rendezvous. She joined the Augsburg, three torpedo boats, a submarine, and three other warships early on the 25th off Hoburgen lighthouse on the southern tip of the Swedish island of Got­ land. There, the officers were told of the plan: The ships were to slip by night behind a Russian minefield believed to protect the entrance of the Gulf of Finland, and attack whatever Russian ships they found.

At 8:30 A.M. that same day, the flotilla set out, moving to the northeast at the fairly high speed of 20 knots. The sailors aboard the Magdeburg, who suspected the presence of enemy armored cruisers, thought the assignment would prove to be just a suicide mission.

By 5 P.M., in a calm sea, the air misty, the navigational plots of the Magdeburg and the Augsburg differed by a mile. But this raised no concern, since the Magdeburg was to follow the flagship Augsburg by half a mile: If the Augsburg struck a mine, the Magdeburg had time to avoid hitting any herself.

Soon, however, fog–common in those waters in summer–rolled in. By 9 P.M. it was so thick that even with binoculars an officer on the bridge of the Magdeburg could not see the lookout on the stern. At 11 P.M. the Augsburg, intending to run along the supposed Russian minefield before swinging east to enter the Gulf of Finland, turned onto a course south-southeast 1/2 point east (151 degrees, 32 minutes, 30 seconds) and ordered the Magdeburg to do the same. She did so, maintaining the same 230 engine revolutions per minute, or about 15 knots, that had kept her at the proper distance from the Augsburg during the afternoon. But she was a mile farther south than her plot showed her to be.

Her captain, Lieutenant Commander Richard Habenicht, had soundings taken. These showed the depth decreasing: 190 feet, 141 feet, and, at 12:30 A.M., now August 26, 112 feet. At the same time the radio shack reported that a message from the Augsburg was coming in; four minutes later it was decoded and on the bridge. It ordered that her course be altered to east-northeast 1/2 point east (73 degrees, 7 minutes, 30 seconds). The helms­ man turned the rudder 20 degrees, and at 12:37, just as he reported that the new course was being steered, still at 15 knots, the luckless vessel hit something. She bumped five or six times and, shuddering, stopped. The cruiser had run aground. As a consequence of her earlier navigational error, she had struck shallows 400 yards off the northwestern tip of Odensholm, a low, narrow island two and 1/2 miles long at the entrance to the Gulf of Finland.

At once, Habenicht sought to get his ship off. He reversed engines. The ship stayed stuck. He rocked her with various engine speeds. He assembled the entire 337-man crew on the quarterdeck to push the Magdeburg‘s stern down and her bow up and then went full speed astern. He had the crew carry munitions aft. The ship didn’t budge. Soundings showed that at the bow, where the Magdeburg normally drew 16 and 1/2 feet, the water to starboard was only nine feet deep; at the stern, with normal draft just under 20 feet, the depth was 13 feet. The vessel needed to rise seven feet.

Habenicht jettisoned the anchors and their chains. He had the drinking and washing water pumped out. Ash ejectors flung coal into the sea. All but 60 boxes of munitions were dumped over the side. All movable steel parts­ the mine–laying rails, bulkhead doors, doors on the forward turrets, steel cables, coaling equipment–were pushed overboard. Habenicht then ran the engines forward and backward at various speeds. The Magdeburg moved not an inch.

The Germans’ efforts were spurred by the likelihood that the officials on Odensholm, which was Russian territory with a lighthouse and a signal station, had alerted superiors at the major Russian port of Tallinn, only 50 miles away. Habenicht worried that the cruiser’s secret documents might fall into Russian hands. In addition to the charts of German minefields and the ship’s war diary, these included the main Imperial German Navy code and the key used to encipher its code words and thus to provide another layer of secrecy.

Lieutenant Walther Bender, who as first radio officer was in charge of destroying these documents, brought one of the codebooks and its cipher key from the steering room to the stokehold and burned it. Sailors did the same for other secret documents. But two codebooks–one on the bridge and one  in the radio shack–as well as a cipher key were retained for possible use in communicating with rescuers and higher commands. A fourth lay hidden and apparently forgotten in a locker in Habenicht’s cabin.

As dawn approached, the seabed and the stones on which the ship was lying became visible. At 8:30, with the fog lifting, the fast and powerful torpedo boat V-26 appeared, attached a line, and tried to pull the Magdeburg off. She failed. Habenicht decided he might as well do some damage and fired about 120 shots at the lighthouse, chipping it, and at the signal station, setting it ablaze. By then the radio shack was picking up many signals from Russian ships; apparently they were on their way. Since all attempts to free the Magdeburg had failed, Habenicht regretfully concluded he had to blow her up rather than let her fall into enemy hands.

Charges were set fore and aft. The crew was to get off the ship and onto the V-26, which was to come alongside. But suddenly a shout rang through the ship: “The fuses are lit!” Habenicht had not ordered this; it had been done by mistake. The vessel would blow up in only four and a half minutes.

In the midst of the tumult that ensued, Bender directed the second radio officer, Lieutenant Olff, to have the codebook and cipher key from the radio shack taken off the ship and onto the V-26. On Olff’s instructions, Radioman Second Class Neuhaus grabbed the codebook and Radioman Third Class Kiehnert the cipher-key papers. The bridge’s codebook was in the hands of Radioman Second Class Szillat. The first officer, unable to find Habenicht as the seconds ticked away, ordered the crew to the afterdeck, where the V-26 was to pick them up. He called for three cheers for the kaiser, had the two ships’ boats lowered, and commanded, “All hands abandon ship!”

Upon hearing this, Szillat flung the codebook he was carrying over the side, toward the stern. It splashed into what he said was a “dark” place about 15 feet from the ship and immediately sank. Then he leaped overboard. Kiehnert, too, jumped into the water, holding the radio shack’s cipher key. He was struck by men following him, and when he came to the surface, he noticed that he had lost the key.

At 9:10 the forward charge detonated. It split the vessel in half, tore open the forepart from near the bow to the second smokestack, and hurled huge pieces of steel into the air. They rained down upon scores of men who were trying to swim to the V-26. Neuhaus, carrying the radio shack’s code, had been seen in the water before the explosion but was missing for a while later; no one knew what had happened to the codebook.

The V-26 picked up many of the swimming men, including Szillat and Kiehnert. Fear of being destroyed in the explosion of the Magdeburg‘s after charge–which never fired–kept the torpedo boat from  coming  near enough to rescue the men still aboard. Meanwhile Russian ships, closing, began to fire at the speedy vessel. One shell swept eight men overboard; another smashed into her starboard side, destroying the officers’ wardroom and killing all who were in it, mainly wounded men from the Magdeburg. But the V-26 got away.

Habenicht, who had appeared briefly on the bridge when he heard the cheers for the kaiser and then vanished again into the bowels of his cruiser, did not abandon ship but awaited his fate on it, together with a few others. Bender and a few dozen sailors, among them Neuhaus, swam to Odensholm, where they were taken prisoner. One of the Russian ships, the torpedo boat Lejtenant Burakov, sent a boat with armed men, led by her first officer, Lieutenant Galibin, to the Magdeburg. The crew members still on board offered no resistance and were taken prisoner. Habenicht, whom Galibin thought “a true gentleman,” offered the Russian his dagger, which Galibin chivalrously declined. The Germans were rowed from both the ship and the island to one of the Russian cruisers and later sent to a prisoner-of-war camp in Siberia.

Galibin lowered the black-white-and-red German naval war flag and raised the white czarist flag with its light blue cross of diagonals. Then, revolver in hand, he searched the wreck of the Magdeburg. He found a locker in Habenicht’s cabin and broke it open. Hidden deep within it was the German codebook, forgotten in the excitement of the catastrophe. Galibin removed it, together with other documents, and had it transferred to the Lejtenant Burakov. The Allies thus came into possession of the key cryptographic secret of the Imperial German Navy–the one that gave them access to many others.

Knowing that possession of the German code books and its cipher keys would be enormously helpful to Britain’s Royal Navy, the Russians loyally notified their allies of the find and said they would give them the documents if the British would send a small warship to escort the officers accompanying the documents to Britain. The Russians courteously set aside for the British the original code, which bore serial number 151, making a copy of it for themselves.

The task of bringing Codebook 151 to England was assigned to two naval captains, Kedrov and Smirnow, and to another naval officer, Count Constantine Benckendorff. A cosmopolitan, moustachioed combat veteran of the Russo-Japanese War, Benckendorff was the son of the ambassador to Great Britain and had served a year as a cipher clerk in the London embassy. He was on watch on the battleship Poltava in the Tallinn roadstead, pacing the quarterdeck and listening to the sailors’ choir chanting the Russian Orthodox mass on a Sunday morning in September, when a yeoman handed him an order to report to the flag captain. On the flagship, he was “amazed and delighted” to be told he would be going to London.

He was given the precious codebook in St. Petersburg. It was in a satchel with a large piece of lead sewn in to make it sink in case he had to throw it overboard. He took the satchel to Arkhangelsk, where he boarded a Russian volunteer fleet steamer. The vessel was to meet the British escort, the aging cruiser HMS Theseus, at Aleksandrovsk (now Polyarny), a port near Murmansk, whence it had arrived early in September from Scapa Flow, the deep, circular, islands-sheltered bay in the Orkneys just north of Scotland.

Owing to the time needed for copying the codebook and to bureaucratic delays and misunderstandings, the Theseus and the steamer did not sail until September 30. After an uneventful crossing over the top of Norway, punctuated only by a few vague U-boat alarms, the Theseus arrived in Scapa Flow on October 10; the Russian steamer, with Benckendorff aboard, went on alone to Hull, arriving there a couple of days later.

After a slow night-train ride, Benckendorff reached the Russian embassy at dawn. He greeted his parents, then routed out the naval attache, and the two went, early on the morning of October 13, to the Admiralty. There, in a moment heavy with history, they handed Winston Churchill, the first lord of the Admiralty, a gift more precious than a dozen jewel-encrusted  Faberge eggs: the big, fat, blue-bound Signalbuch der Kaiserlichen Marine.

It went at once to the fledgling group of codebreakers set up at the outbreak of war by the director of naval education, Sir Alfred Ewing, an engineer who had long been interested in ciphers.  A short, thickset  Scot, given to wearing mauve shirts with white wing collars, he was a good friend of the director of naval intelligence, who had asked him to see what he could do with the encoded German radio messages being intercepted by British stations. Ewing had gathered some instructors in German from the Royal Naval Colleges, sat them around a desk in his cramped office, and, with them, examined the intercep. But though they classified the messages into different kinds based on their appearance and addressees, they had not been able to read any of them.

Now, two months later, the German naval codebook landed on their desk. It contained hundreds of pages of columns of five-digit groups and three-letter groups standing opposite the German words they were to replace. For example, 63940 or OAX were the secret substitutes for Oktober. The encoder looked up each word of his message in the codebook as in a dictionary and replaced it with the five-digit code number or more, usually the three-­letter code word next to it. The succession of these code numbers or code words formed the secret message, or cryptogram. But British attempts to decipher the intercepts by this simple method still did not work. Some code words could not be found in the codebook, and those that could produce gibberish.

Gradually the British discovered that the letters of the code words had also been disguised. Other letters replaced them, so that the codebook’s OAX might become the transmitted JVM. By early November the British had worked out the letter substitutes and were able to read many German naval messages.

Among the first were some that dealt with a possible ambush. The German naval commander, encouraged by the success of a bombardment and mine-laying off the British port of Yarmouth, which some Britons feared presaged an invasion, decided to repeat the action with two ports in northern England, Scarborough and Hartlepool. He hoped to lure some British battle cruisers into the arms of his full High Seas Fleet, destroy them, and thus regain at least near-parity with British naval forces. On December 14, 1914, his scouting-force commander, Vice Admiral Franz von Hipper, wired a request for extensive aerial reconnaissance to the north, northwest, and west on the next two days. He added that German forces would sail from their roundish harbor in the estuary of the Jade River at Wilhelmshaven at 3:30 A.M.

The British intercepted and deciphered the message. It went to retired admiral Sir Arthur Wilson, a former first sea lord (equivalent to a U.S. chief of naval operations) who had returned as Churchill’s adviser on intelligence and other matters. At 7 P.M. on the 14th, he brought it to Churchill, who summoned the first sea lord and the chief of staff. What did it mean? It specified no objective, but Wilson said that it probably indicated a movement of the German battle cruisers against English coasts and that the High Seas Fleet as a whole seemed not to be involved. The others agreed with his conclusions, though they acknowledged that hypotheses were needed to bridge the gaps in the evidence.

Within hours the Admiralty ordered units of the British fleet to proceed at once to a “point where they can intercept the enemy on his return.” But thinking the German battleships were staying in port, the Admiralty refused to let more than a single squadron of British battleships sail from their home base of Scapa Flow. The commander of the British Grand Fleet, Admiral Sir John Jellicoe, chose the perfect intercept point: on an almost direct line between Scarborough and the German island fortress of Heligoland off Wilhelmshaven.

The Germans sailed at 3 A.M. on December 15, the British soon thereafter. By the morning of the 16th, the Germans were bombarding Hartlepool and Scarborough. Churchill, notified in his bath at 8:30, hopped out, put his clothes on over a damp body, and hurried downstairs to the War Room. The admirals assembled there were confident of their dispositions, but they knew that weather in the wintry North Sea could shut down visibility, and thus the possibility of contact, within minutes. What they did not know was that, despite their assumptions, the whole High Seas Fleet had sailed. If it met with the reduced force of British ships, it could destroy the British squadrons and regain the equivalence in forces that could change the course of the naval war.

Indeed, in the predawn blackness of December 16, one of the German destroyers ran into the British advance screen. The contact created the very situation that the Germans had sought since the start of the war. But the German commander did not recognize it. Believing himself to be confronted by the whole of Britain’s Grand Fleet, and mindful of the kaiser’s fears about losing the navy, he turned for home. He thus lost the greatest opportunity the German navy was ever to have.

Meanwhile, Hipper’s forces were likewise racing for home after the bombardment. British intelligence had placed their ships so precisely in Hipper’s path that at 10:30 A.M. the light cruiser Southampton spotted them. But fog and rain were reducing visibility, and before either the Southampton or the heavier British forces could attack, Hipper’s ships escaped behind the veils of mist, reaching home safely.

The British were angry and disappointed. Not only had the navy failed to defend Britain’s coast, it had failed to sink any Germans. Their anger was compounded by frustration. Churchill later said that he had to bear in silence the censures of our countrymen. We could never admit for fear of compromising our secret information where our squadrons were, or how near the German raiding cruisers had been to their destruction. One comfort we had, the indications upon which we had acted had been confirmed by events.

Similar indications came the next month. Wilson strode into Churchill’s office around noon on January 23, 1915, and said, “First Lord, those fellows are coming out again.”


“Tonight. We have just time to get Beatty there,” he said, referring to Vice Admiral Sir David Beatty, commander of the battle cruisers. Wilson explained that the codebreakers had read a message sent at 10:25 that morning to Hipper, ordering a reconnaissance of the Dogger Bank, a sandy shallows in the North Sea about 60 miles east of Britain.

Britain elected to use the same tactics as before, and units under Beatty sailed to block the German homeward trip. This time they were luckier. Contact was made at 7:30 A.M. on January 24 at a point on the Dagger Bank. When Hipper saw the numerous English forces, he followed directives, col­lected his ships, and ran. The British, in their faster, super dreadnought-class battleships, gave chase. By 9 A.M., the Lion, carrying Beatty, opened fire at 20,000 yards (11 miles). The action soon became general between the four British and four German capital ships. The Blücher was sunk and the Seydlitz and Derfflinger heavily damaged. Confusion in the British squadron after a shell crippled the flagship permitted the German ships to escape. Nevertheless, the Germans staggered into port, flames leaping above their funnels, their decks encumbered with wreckage and crowded with the wounded and the dead. The German ships did not stir out of port again for more than a year.

The codebreakers had by this time expanded slightly and taken up the quarters in the Admiralty’s Old Building that soon gave them their unofficial name: “Room 40, O.B.” The Battle of the Dogger Bank earned them the confidence of the Admiralty, and shortly afterward the terrifying Lord John (“Jackie”) Fisher, the builder of the dreadnought fleet who had just returned as first sea lord, gave Ewing carte blanche to get whatever he needed for the betterment of his work. Ewing augmented his staff, added to his intercept and radio direction-finding stations, and improved their equipment.

But some of Room 40’s effectiveness was lost due to excessively tight control by the director of the operations division, Captain Thomas Jackson. Boorish and self-opinionated, Jackson distrusted civilians’ ability to deal with naval affairs and was unpleasant to them. He hardly visited Room 40 at all, and on one of those occasions came only to complain that he had cut his hand on one of the red boxes in which the intercepts were circulated. Another time, when a change of cipher key temporarily interrupted the flow of solutions, he called to express his relief that he would not be further bothered by such nonsense. This attitude was to have grave effects.

In the late spring of 1916, the new commander of the German High Seas Fleet, Vice Admiral Reinhard Scheer, was chafing at his inactivity. He decided to try to repeat, with a variation, some of the tactics that sought to bring parity between his fleet and his enemy’s. He would attempt to entice the British Grand Fleet to where his submarines could attack it and his High Seas Fleet fall upon a section of it without risking a general engagement.

His orders, however, lay at the mercy of British radio intelligence. Crypt­ analysis was part of this; another was radio direction-finding. In this, radio stations take bearings on the emissions of a transmitter from two or more points; a control center plots these bearings on a map, and the transmitter is located where they cross. Successive plottings can determine the movement of a transmitter, its direction and speed.

It seems to have been such intelligence that led the Admiralty to inform its forces at 5 P.M., May 30, 1916, that the High Seas Fleet was apparently about to put out to sea. At this news, virtually the entire Grand Fleet, that mighty armored pride of England, built up steam and sallied forth majestically from Scapa Flow, Invergordon, and Rosyth. It sought a major fleet action that would give England the undisputed control of the seas on which her strategy in the war so heavily depended.

There then occurred one of those trifling errors on which history so often turns. On sailing, Scheer had transferred the call sign DK of his flagship Fried­ rich der Grosse to the naval center at Wilhelmshaven in an attempt to conceal his departure. Room 40 was aware of this procedure, but it was the insufferable operations director, Captain Jackson, who came in on May 31 to ask where call sign DK was. He was not the sort of person to whom one offered unsolicited advice, so he was merely told, “In the Jade River.”

Jackson passed along this message, and the Admiralty thereupon radioed Jellicoe that directional wireless placed the enemy flagship in the harbor at 11:10 A.M. Three hours later, with Jellicoe believing that the Germans were still in port, the two fleets made contact in the middle of the North Sea.

This rather shook Jellicoe’s faith in Admiralty intelligence. It was further jolted when he plotted the position of the German cruiser Regensburg as given by the Admiralty report and found that it appeared to be in almost the very same spot as he himself then was! At the time no one knew that the Regensburg navigator had made an error of ten miles in his reckoning and that blame for the absurd result lay with the German officer, not with the cryptanalysts of Room 40 reading the German report of the ship’s position.

After the brief flurries of action, damaging but inconclusive and unsatisfactory to both sides, that constituted the Battle of Jutland, Scheer at 9:14 P.M. ordered: “Our own main body is to proceed in. Maintain course SSE 1/4 E; speed 16 knots.” At 9:46 he altered it slightly to south-southeast 3/4 point east. Both messages were decoded with almost unbelievable alacrity by Room 40, and by 10:41 a summary of them had been received aboard the flagship.

But Jellicoe had had enough of Admiralty intelligence. Furthermore, the summary had omitted Scheer‘s 9:06 call for air reconnaissance off the Hom Reefs, which would have confirmed his intentions to head for home, and thus there was nothing to contradict a battle report from the Southampton that suggested a different enemy course. Jellicoe therefore rejected the Admiralty information, which this time was right. As a result, he steered one way, Scheer fled another, and Britain’s hope of a decisive naval victory evaporated in a welter of errors, missed chances, and distrust.

But if Room 40, through no fault of its own, did not enable Britain to win a major naval battle, it did play a critical role in helping her to win the war.

In 1917, Germany on one side and Britain and France on the other were gasping in exhaustion from a war that both had thought would be over-as the kaiser said-“before the leaves fall” in 1914. Germany thought she saw a way to win: Unrestricted submarine warfare would starve the Allies into submission. She recognized that this would probably bring the United States into the conflict against her. But her new foreign minister, Arthur Zimmermann, thought of a way to neutralize this danger. He would distract America by getting Mexico to wage war on her. And he would persuade Mexico to do this with an offer she could not refuse: Upon victory, Mexico would get back the territories she had lost in the Mexican-American War of 1846.

He put his proposal into code and cabled it on January 15 via Sweden to the Western Hemisphere. But the cable touched British soil. The British intercepted the message, and Room 40 deciphered it. The director of naval intelligence, Captain Reginald Hall, whom the American ambassador called a genius (“all other secret service men are amateurs by comparison”), saw that he had a propaganda weapon of the first water. With permission, he gave it to the Americans. President Woodrow Wilson, stunned by the German proposal, gave it to the Associated Press. The story made headlines in papers all over the nation on March 1. The isolationist Midwest, previously unconcerned with the distant poppings of a war in Europe, jerked awake at the thought of a German-officered Mexican army advancing up toward Chicago. Five weeks later President Wilson–who had been reelected just months earlier on the slogan “He kept us out of war”–went up to Capitol Hill to ask Congress to “make the world safe for democracy” by declaring war on Germany. Congress complied. And soon the fresh strength of the young nation was pouring into the factories and trenches of the Allies. The Germans were driven back and back until they had no choice but to surrender. The code­ breakers, who had gotten their start with a codebook recovered from a stricken German warship at the beginning of the war, had played a major role in bringing that war to an end.

POSTSCRIPT: For the 25 anniversary of the Magdeburg‘s stranding, the old battleship Schleswig-Holstein was sent to Poland to commemorate the cruiser’s dead, who were buried in a Danzig cemetery. The ceremonies lasted a day, but the battleship remained moored at the port as tension between Poland and Nazi Germany mounted. At 4:48 A.M. on September 1, 1939, her 11-inch guns roared, shattering and setting ablaze some Polish installations on the Westerplatte, a sandy tongue of land. The shots were the first of World War II.


This article originally appeared in the Winter 1990 issue (Vol. 2, No. 2) of MHQ—The Quarterly Journal of Military History with the headline: The Magdeburg


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