How Vice-Admiral Cronstedt surrendered the strong fortress Sveaborg to Russia in 1808

By Carl O. Nordling

(From an article published in The Journal of Slavic Military Studies, Vol. 17)

Summary:

In the middle of the Napoleonic wars Czar Alexander of Russia started a war against Sweden, which then comprised both its present territory and the area east of the Gulf of Bothnia nowadays constituting the state of Finland. Sweden’s foremost defensive works at the time was the newly built fortress of Sveaborg on some islets at the northern coast of the Gulf of Finland about one mile off the small town of Helsingfors, now better known as Helsinki. The fortress was strong enough to withstand storm and its garrison and stores were sufficient to sustain a siege for several months. In spite of this Sveaborg surrendered to the Russians within a number of weeks. It was the personal qualities of the two chief adversaries, General Jan Pieter van Suchtelen on the Russian side and Vice-Admiral Carl Olof Cronstedt on the Swedish side, that determined this gratuitous outcome.

Introduction

The Napoleonic Wars involved most European countries into their turmoil. In a peace treaty 1807 between Napoleon and Czar Alexander I, the latter promised to attack Sweden in order to force her to join the Continental Blockade against England. The natural reward for this undertaking was that a successful war would leave Alexander in possession of a large part of Sweden, viz. the part on the east side of the Gulf of Bothnia, which was commonly called Finland. Alexander fulfilled his obligation and started the so-called "Finnish War" in February 1808. The war lasted more than a year but Russia had as good as won it already with the capture of the strong Swedish fortress of Sveaborg in May 1808.

Sveaborg that is built on six small islands off Helsinki had been called the Gibraltar of the North. The English historian William Coxe had seen the fortress in its uncompleted state about 1785, and he estimated that already then it would be strong enough to dishearten any enemy wanting to capture it. He considered that when ready built, it would deserve to be called the Gibraltar of the North.¹

As it happened, Sveaborg was completed when it came under siege 23 years later. The so-called "Finnish War" started with Russia attacking Sweden on 21 February 1808. The Russian Army under Count Friedrich Wilhelm von Buxhoevden (1750-1811) advanced rapidly and reached Helsinki on 2 March. The investment of the fortress could begin.

The commandant of Sveaborg since 1801 was Vice-Admiral Carl Olof Cronstedt (1756-1820). Already on 1 February he had received an alarming report from the Swedish Ambassador to St. Petersburg. The Swedish troops in Finland were mobilized and about 4,500 men from the mobile army were stationed in Sveaborg together with the garrison of about 2,250. Cronstedt thus had a considerable force at his command, a force whose numerical strength the beleaguering army was not going to surpass during the siege.

A force of the Russian Army, consisting of about 2,000 troops, occupied Helsinki in the beginning of March and billeted itself in the townsmen's houses. (There were probably about 600 households with 2,800 members at the time - one third of the combined population of Helsinki and Sveaborg².) About the end of he same month the Russians sat up batteries on the headlands on both sides of the little town. But already on 19 March the Russians began bombarding the fortress with a few guns from a couple of islets between these headlands. The shelling caused some insignificant damages. Cronstedt, however, soon accepted the Russian proposal to enter into negotiations. These began on 23 March and resulted in the conclusion of a truce on 6 April. The settlement implied that the truce should remain in force until the fortress was succored by at least five ships of the line. In case no relief had arrived by 3 May, the fortress and the Coastal Fleet should be made over to the Russians together with all their stores. Three islands with outpost fortifications were delivered at once. On 3 May the sea was still covered with ice and no succor had arrived. Consequently, the main fortress was contractually handed over to the Russians on that day. How could General Buxhoevden achieve such an enormous advantage in so short time with so inadequate forces?

The alleged unfitness of the fortress

The obvious answer is that Cronstedt gave it to him. But why should the commandant surrender an unbeaten fortress to an inferior enemy force? As Cronstedt himself argued, it was his task to retain Sveaborg as long as possible³. From 22 March the fortress was invested⁴. A couple of weeks later he realized that the ammunition would suffice for no more than another couple of weeks of artillery duel. Confronted with this fact, he accepted the treaty in order to extend the perseverance so much more as to give the High Sea Fleet in Karlskrona a fair chance to succor the fortress. As it was, he managed to keep Sveaborg two months from the date of the Russians' arrival to Helsinki. Cronstedt felt that he should deserve credit for this, not censure.

Was he right? Would an attempt to keep Sveaborg right up to the summer months have been a forlorn hope? Are perhaps fortresses generally nothing more than flashy buildings without appreciable value in case of war? Even the mighty Maginot Line was, after all, a big fiasco, wasn't it?

The German-Finnish historian Hanns Heinz Ollus⁵ has enumerated a great number of deficiencies that were inherent in Sveaborg at the outbreak of war in 1808. He found that wells were scarce, that many buildings had wooden roofs, that gunpowder supply was scarce, that light flares were missing, that the cannon sloops were stored in wooden sheds visible from the outside and that the hospital barracks was not bomb-proof. Apart from the deficiencies and unlike Coxe, Ollus disowned Sveaborg of appreciable military value because he considered it to be both misplaced and misconstructed. It had no moat and the originally planned external fortifications east and west of Sveaborg had not been built. The result was that the fortress was placed as if in a valley, open to observation from the surrounding hills on the mainland and the large island Skanslandet--the very places of the missing outer bastions. Therefore, said Ollus, the fortress would be checkmate as soon as an enemy sat up guns on Skanslandet. In short, his opinion was that Sveaborg could not defend itself. Consequently, it would have fallen in case the enemy had stormed. In such a case its garrison and all the civilians would have been a fair game to the sack and caprice of the victor.

As Ollus saw it, Cronstedt managed to prevent such a catastrophe, which proves that he acted wisely. Count Augustin Ehrensvärd (1710-72) is the one to blame for the fall of Sveaborg, because he planned and built such a useless fortress.

This sounds attractive enough, but although the deficiencies did exist, the conclusions drawn by Ollus do not necessarily hold good. For instance, the scarcity of wells is irrelevant since the seawater around Sveaborg holds less than 0.5 percent of salt and can therefore serve a number of purposes. Even the fresh water supply could be eked out by means of melting snow, of which there was no shortage. Besides, after the thawing of the frozen soil (in May) more wells could have been dug out.

As regards the wooden roofs, they were certainly vulnerable to artillery fire, but with so many hands available, fires could be extinguished as soon as they started if only close surveillance was organized. Most of the wooden buildings could have been saved without wasting gunpowder on combating the enemy artillery. And when all is said and done, a fortress does not fall with the loss of its storehouses, stables and sheds, not even of its mills.

Nor would it have been necessary to waste gunpowder on test-shooting with the guns, as Ollus imagines, because there was no need to score hits on far away targets. The profitable use of the guns was, of course, to shoot at storm troops at a short distance. For this purpose even untested guns would be effectual. Besides, some of the guns were tested and could be used for precision shooting if such would be really needed.

A really bizarre argument for the wisdom of the settlement with the enemy is Ollus's reference to the need of gunpowder for the Coastal Fleet, which would have meant a serious shortage of powder for the defense of the fortress itself. Sveaborg contained a considerable part of the Swedish ground forces, intended for a summer campaign together with reinforcements planned to be landed some time after the break-up of the ice. It was the duty of the Commander to save these forces and the fortress in the first place, not to keep the Fleet fit for active service. If the main purpose could be achieved, the Coastal Fleet would be saved in addition, with or without its necessary gunpowder. If the fortress had to be given up, the Coastal Fleet should of course have been burnt in advance and would not have needed any gunpowder. Cronstedt had explicit orders to burn the fleet with all its stores rather than risk it to fall in to enemy hands⁶. As long as the Coastal Fleet was in Swedish possession (even if not fully operative) the Russians could not attain naval superiority in the archipelago. Just as long the possibility existed to land Swedish reinforcements in the rear of the Russian Army.

The real shortages were to be found on the Russian side. The besiegers were e.g. not equipped with the kind of incendiary rockets and bombs that the English had used against Copenhagen in 1807 to the number of 400 and 6,000 respectively. Burning down more than 300 buildings had compelled Copenhagen to surrender within five days.⁷ Without incendiaries, the Russians had slight prospects of destroying even the wooden houses on Sveaborg. And, more important, in April the melting away of the snow and the following period of ground thawing were imminent, which meant that the roads would be impassable in the meantime. During this period the Russians could not expect to receive any heavy consignment to replenish their insufficient supplies of guns and ammunition.

As it happened, Cronstedt saved so much gunpowder that he could give away not only the fortress but also the intact Coastal Fleet equipped with as much ammunition as it could possibly carry.

Obviously Ollus went wide of the mark. Instead, let us listen to Cronstedt himself. In his printed apology³ he says that he could not have imagined an attack against Sveaborg in winter from the land side. He mentions that the fortress was not fit for defense when he took office as Commander (i.e. 1801), and points out that the fortifications were spread out and not continuous. He says that 6,000 troops had been detailed as a garrison for Sveaborg, which was insufficient, but that he ended up with only 4,700 troops. Furthermore he argues that it would have been sheer madness to make a sally, since the enemy could spread himself out everywhere around the fortress. He also makes the clearly untruthful assertion that Sveaborg was entirely open on the land side. He agues that he had only 89 tons of usable gunpowder, which would have been used up in 15 days, whereupon he would have been forced to unconditional surrender. If he had found himself compelled to continue firing 30 shots a day with every gun, he had certainly been forced to surrender Sveaborg on 10 April. By means of his consummate stratagem the fortress held on three weeks longer!

According to available sources, the garrison numbered 6,750 men, not 4,700.⁹ Also Cronstedt ignores the fact the Russian force did not exceed 2,000 during the two first weeks of March when a sally obviously could have proved to be disastrous for the Russians. And he does not give the faintest of reason for the excessive shelling that would have caused the supply of gunpowder to run out if it had continued. Crontedt's apology is not very pertinent, to say the least.

Historic sieges

But even if Ollus and Cronstedt are wrong on most points, they may of course happen to be right on the critical issue. Should Ehrensvärd after all be censured for his headstrong work with building a fortress on the six islets called Vargskären ('Wolf's Skerries')? Are fortresses perhaps generally more or less worthless - at least when resources are running short?

No, the odds are not against fortresses in general. The Swedish fortress Nöteborg ('Nut Castle') by River Neva is well known in the history of Sweden and Russia. In 1656 it was in rather bad repair and had a garrison of 120 men. The Russian laid siege to it during four months and then offered the Commander to accept an honorable surrender. They received the historic answer: "Apples and pears will be given, not such a Nut".¹⁰ The Russians stayed five more weeks and then left without having achieved anything.

When Nöteborg finally surrendered in 1702, in another war, it had sustained three storms and had only 40 effectives left, out of a garrison of 250. Reportedly, the enemy lost about two thousand men.

In 1700 the fortified town Narva in Estonia had a garrison of 2,000 who defended the town in more than two months against 32,000 beleaguering Russians, until the town was relieved by a force of 10,000 under King Charles XII.

The British fortress Gibraltar was enveloped during four years, from 1779 to 1783, by French and Spanish forces. Famine ensued, but the fortress held on and the enemy gave up. Then, in 1783, Cronstedt was 27 years old and served on a fortress, viz. Sveaborg. He could hardly fail to be influenced by the event.

Even long after 1808 a number of fortresses proved to be important links of the total defense. Sevastopol held on for almost a year before the English captured it in 1855; Mafeking in South Africa was defended by 1,250 Britons under Colonel Baden-Powell. The Boers laid siege with 9,000 men, but Mafeking held on in seven months until it was relieved in May 1900.

Also Tobruk in North Africa held on in seven months against the Italians until the Britons succored it in 1941. Lorient and Saint-Nazaire in France withstood the Americans in eight months and did not give up before the general capitulation in May 1945.

Could Sveaborg have been marred by some serious defect that made it much more vulnerable to shelling and storming than the above examples? Accidentally, we are in a position to know a great deal about the hardiness of Sveaborg. During the Crimean War, in 1855, Sveaborg was bombarded with heavy artillery from points outside the range of its own guns. Within two days a fleet from the British and French navies heaped upon the fortress 20,000 missiles weighing on average 50 kg, i.e. altogether 1,000 tons. This was nearly 70 times more than the weight of the 1,565 bullets that hit Sveaborg during five days in 1808. The 1855 bombardment resulted in 62 killed and 199 wounded, that is to say about seven times the total loss in 1808. However, the Russian Commander of Sveaborg did not strike his colors or beg for mercy (as did his colleague on Russian built fortress Bomarsund on Åland the year before).

The situation of Sveaborg in 1808

In the winter 1808 the Russians had nowhere near 1,000 tons of ammunition, nor could they possibly convey such a quantity before the break-up of ice. Their adversary did not need to be clairvoyant to realize this. It is, and was, obvious that Sveaborg had a very good possibility to sustain any bombardment that the Russians were capable to achieve in 1808. There was no risk of famine either. Even Cronstedt considered the provisions as fully sufficient. "But one does not fight with provisions" said he--quite rightly, but missing the point. The fact is that there was no need to fight before storming was attempted. In 1855 Sveaborg did not fire a single shot, yet did not fall. It was Cronstedt's duty to maintain the fortress, not to beat the enemy. No matter how much the Russians had bombarded, they could not have subdued Sveaborg without storming. And on 6 April they could count on the ice to bear storming troops only during three more weeks at most. They did not have any possibility to damage the fortress even half as badly as the French and Britons did in 1855. To transport large amounts of ammunition overland from Vyborg or St. Petersburg to Helsinki was simply not feasible, a fact certainly well known to Cronstedt from his duties in that region during the Russo-Swedish War 1788-90.

If the Russians had ventured on a storming, Sveaborg had (in a usable state) 127 "six pound cannons" and 77 "three pound cannons", that is to say guns that could fire cartouche shells weighing 2.6 and 1.3 kg respectively. There was 26 tons of ammunition of these types--to compare with the 15 tons that the Russians had scattered over Sveaborg. The two Swedish experts Claëson and Grenander have calculated that one well-aimed cartouche could wound about 18 men out of an advancing column at a distance of 100 m¹¹.

A reasonable force to man all the necessary stations in the event of a real threat would have been 2,500 troops. Consequently Cronstedt had a reserve of 4,000 men. Five percent of the powder supply would have lasted several hours for shooting at storming troops. If the enemy had advanced right up to a stone's throw before the walls in spite of the cartouche shelling, there were 18,000 hand grenades ready for use, beside all the rifles, of course. Finally, if the survivors of such carnage had proceeded all the way to the walls and had begun to put up ladders, they could have been confronted with long wall pikes from above. Every sensible commander would realize that such an attempt would be doomed to failure, and so did Buxhoevden. Cronstedt, however, seems not to have seen this enormous advantage of his own fortress. And Buxhoevden was lucky to have at his disposal a very special "war equipment", i.e. the Dutch-born General-Engineer Count Jan Pieter van Suchtelen (1751-1836). Suchtelen had left his native country for Russia in 1783. He had participated in the 1788-90 Russo-Swedish war and had thereafter superintended fortification works and canal building. In 1808 he was appointed Quartermaster-General under Buxhoevden. His diplomatic talents were extraordinary to say the least. As it happened, these talents proved to be vital in order to subdue an unusually strong fortress that was also equipped with at number of casual advantages.

Possible measures

Let us consider what the Commandant could have done except just playing the hedgehog. First of all: If he considered it impossible to keep the fortress, he could - and should - have told his superiors that much. They could then have replaced him by a person who was confident enough for the job.

A commandant firmly resolved to keep the fortress would have prepared himself by studying a few sieges well known from recent wars, e.g. those of Älvsborg and Varberg in the Seven Years War (1563-70), of Narva in 1581, of Kalmar Castle in 1611, of Älvsborg in 1612, of Riga in 1621, of Stralsund in 1628, of Nöteborg in 1656, of Narva in 1700 and of course the very recent and very renowned siege of Gibraltar in 1779-83. From the histories of these sieges one could learn, among other things, the significance of treason and false reports as means to capture a fortress and, consequently, the utmost importance of being on his guard.

And if the officer in question had not profited by a military education including the epoch-making work of Marshal Sébastien Vauban, De l'attaque et de la défense des places from 1742 (or its German translation from 1770), then a thorough study of this work would have been mandatory. Such a study would probably have resulted in looking at Sveaborg as almost an ideal fortress for applying the offensive elements that Vauban emphasizes in his book.

Apparently, the Commandant could have taken the following measures even after the outbreak of war:

1. Send away most of the 4,000 civilians, viz. all the soldiers' wives and children and also such personnel that were not fit for taking part in the defense. These could be accommodated with farmsteads in the countryside. Keep cooks, tailors, barber-surgeons, pharmacists, nurses, pyrotechnicians, and interpreters.

2. Supplement the equipment with horses, sledges, binoculars, signal rockets, skies, skates, medicine, dressing material, etc.

3. Evacuate Helsinki by accommodating all its 2,800 civilians with manors and farmsteads in a zone about 20 to 50 kilometers from the town.

4. Deprive the enemy of ready billeting by burning down the wooden houses that constituted the town - probably less than five hundred.

5. Send a secret message to Stockholm containing information of the resources and needs of Sveaborg - preferably with a reliable officer in disguise.

6. Deliver a speech to the garrison of each of the islands pointing out the endurance of the fortress and its capability to ward off an assault. Hold up Gibraltar as a model for its northern counterpart to live up to.

7. Fortify temporarily the hills nearest outside the fortress, viz. on the peninsula on the west side and on the large island on the east side. This could be done in the form of a few bulwarks made of logs and equipped with a couple of light guns (weighing c. 400 kg).

8. Set up a permanent watch on these bulwarks and between them and the main fortress. Assign a minor part of the 18,000 hand grenades to the watch patrols - beside their own muskets and bayonets.

9. Organize purposeful activity for the entire garrison in the form of sawing channels through the ice, building obstacles on the ice, making pyres and dummies, and training defense against assault, fire protection and fire fighting, cannon service,

10. Occasionally send out mounted patrols for scouting and sabotage.

11. Organize spying activity on the mainland in the guise of local fishermen and peasants.

12. Refrain from and prevent all verbal and written contacts with the enemy, save for espionage.

13. Invent the stocks of gunpowder and ammunition and allocate the resources into three categories: The necessary minimum for the Coastal Fleet (e.g. 1/3), an amply sufficient amount to be used against storming troops and enemy artillery during assault (e.g. 1/6) and the rest to be used for combating enemy artillery positions and fortification work (about 1/2)

14. Limit the daily consumption of gunpowder of the third category so that firing could continue well into the summer. Prohibit firing for gunnery practice, testing guns and the like. Prioritize firing on enemy guns that are apparently trying to shoot a breech in he walls.

15. As far as possible, place ready tested guns in positions suitable for fighting the most dangerous positions that the enemy might use (for shooting breeches in the walls).

16. Accomplish a high degree of fire extinguishing preparedness by tearing down unnecessary wooden buildings, by storing water in a great number of warm spaces, and by keeping permanent watch in attics under wooden roofs.

17. Keep ice channels open on places where assaults by the enemy are most likely to pay off.

18. Erect pyres outside the walls for illuminating any group assaulting by night over the ice.

19. Erect pyres inside the walls for setting on fire in case of prolonged enemy cannonade. This in order to entice the enemy to assault and thus to lose a considerable part of his force.

20. Occasionally carry out raids against enemy advanced campsites in order to damage them and to take prisoners for interrogation.

Out of these 20 possible measures only a few were actually carried through. Cronstedt ordered the tearing down of a few wooden buildings, the sawing of channels and some occasional raid of armed reconnaissance outside the fortress.

Instead he did some other remarkable things. For some reason, he considered himself not to be bound by the existing rules that forbade a commandant to leave his fortress during a siege. As soon as General van Suchtelen proposed it, Cronstedt entered into negotiations with the enemy outside the walls of Sveaborg. He thereby exposed himself to Suchtelen's cunning methods of psychological warfare, the purpose of which was to break his will to defend his fortress. These negotiations very soon lead to an agreement implying that he gave away three of the six islands constituting Sveaborg. At the same time he promised to give away later not only the remaining three islands, but also all the guns, all the ammunition, all the gunpowder and the entire Coastal Fleet with its 94 craft still intact. The Russians did not have to bother with even a preparation for an assault in order to achieve all this.

Cronstedt's mode of action was, of course, an open-and-shut case of treason. His many pieces of neglect are trivial in comparison, likewise his squandering of no less than one third of all the gunpowder in just ten days--to no use at all. Sveaborg could have endured the siege without discharging a single shot, and occasional shelling at enemy positions here and there made no difference.

The overall war situation as a motive

Given that Cronstedt committed treason, quite formally, could it be that he all the same acted in the interest of his country and its government? If a certain territory is irrevocably lost to the enemy, and if an acknowledgement of this fact may promote the attaining of peace, then giving up an isolated fortress within the territory would certainly appear to be reasonable. Was this the situation, and did Cronstedt actually act according to a sensible judgment of the inevitable outcome of the war?

In the first place, Sweden's defensive war was not lost in April 1808. Admittedly, the Russian army had advanced very far north, pursuing the Swedish forces. Cronstedt could not know just how far the retreat had reached, but he certainly did know that this retreat tallied with the strategic plan that was drawn up by the Supreme Commander on the eve of the war.

Cronstedt also knew that he had been entrusted with about 30 percent of all the Swedish ground forces available on the east side of the Gulf of Bothnia - beside the Coastal Fleet and the fortress. He knew that the strategic plan implied a pincer movement during the summer season, when the southern leg of the pair of pincers would consist of the Sveaborg forces enlarged by reinforcements from the other side of the Gulf of Bothnia. Also naval operations were anticipated and could prove crucial, especially if a British battle fleet would join the war in the Gulf of Finland. The Britons actually did just that in July 1808,¹² but then there were no Swedish ground forces in southern Finland any more, and the Sveaborg Coastal Fleet already served as a part of Russia's naval forces. Obviously, Sweden's general strategic situation was by no means hopeless in April, and Cronstedt had no reason to judge it as such.

Cronstedt's competence and Suchtelen's

The fact that Cronstedt did not make use of most of the means that he had at his disposal seems to indicate that he was either utterly incompetent or a purposeful traitor. There is, however, nothing in the previous history of Cronstedt to indicate that he was either. Therefore, let us consider a third possibility, namely that he was just moderately incompetent and not decidedly alien to treason. This combination could have been enough to make him accept talks with the enemy. The rest would have been mastermind Jan Pieter van Suchtelen's handiwork. The latter may well have been capable of converting a somewhat wavering Commander into a full-fledged traitor by means of using advanced psychological devices. Since there are no protocols extant from their talks, we will never know just how skilful he was and what ruses he used.

References:

1. Coxe, William, Travels in Poland, Russia, Sweden and Denmark. London

1784-90.

2. Lilja, Sven, Städernas folkmängd och tillväxt, Stockholm 1996, p. 72.

3. Cronstedt, Olof, Sanna upplysningar ... Stockholm 1811.

4. All about the siege and the convention is taken from: Hornborg, Eirik, När riket sprängdes. Helsingfors 1955, pp. 77-86.

5. Ollus, Hanns Heinz, "Sveaborgs undsättning 1808", Meddelande nr 45-46 från

Armémuseum. Stockholm 1986.

6. Odelberg, Wilhelm, Sveaborgs gåta. Malmö 1958, p. 39.

7. Lademann, 23, s. 120; Salomonsens Konversations Leksikon, 14, p. 84; Westerbeek Dahl, B. & Gamrath, H., København før og nu - og aldrig, vol. 11, København 1991, pp. 174-175.

8. Odelberg, Wilhelm, Sveaborgs gåta. Malmö 1958, pp. 110-112.

9. Hornborg, op.cit., pp. 266-267, note 3.

10. Munthe, Ludvig, Kongl- Fortifikationens historia, II. Stockholm 1906, p. 313.

11. Claëson, Sten and Grenander, Gunnar, "Sveaborgs artilleri 1808", Meddelande nr 52 från Armémuseum. Stockholm 1992.

12. Carlsson, Sten, Gustav IV Adolfs fall. Lund 1944, p. 112.

Back to Scandinavian History