Causes of the Austro-Prussian War (1866)
The Convention of Gastein of August 14, 1865, provided for joint Prussian and Austrian sovereignty over Schleswig and Holstein. Austria would administer Holstein, and Prussia would have charge of Schleswig. Lauenburg was awarded to Prussia outright in return for a payment of 2.5 million thalers. Austrian Schleswig was thus an enclave within Prussian territory.
Bismarck now skillfully worked to create tension between Prussia and Austria to bring about war. He was confident that Prussia could defeat Austria militarily, but he needed to secure the neutrality of the other major powers. Russia was still grateful to Bismarck for his actions in helping to put down the Polish revolt of 1863 and also wanted to see Austria humbled for having blocked its aspirations against the Ottoman Empire.
France was another matter, however. For centuries French interests had been served by a divided Germany. In October 1865, Bismarck met with French emperor Napoleon III at Biarritz and secured French neutrality by allowing Napoleon to believe that, following a Prussia victory, France would be allowed to annex Belgium and Luxembourg or receive other territorial compensation along the Rhine. On his part, Napoleon expected Austria to win the war or for it to be lengthy, as the last war between Prussia and Austria had lasted from 1756 to 1763. If protracted, France could enter the conflict late and dictate a settlement advantageous to itself.
Napoleon actually encouraged the war, urging Bismarck to take the Kingdom of Italy as an ally to tie down Austrian forces in the south and receive Venetia from Austria in compensation. Napoleon could thus gain credit with Italy as furthering Italian unification.
In November 1865 the Prussian government offered to buy Holstein outright from Austria in a cash settlement, as with Lauenburg. Vienna refused. This may have been Austrian emperor Franz Joseph I’s worst mistake, for had Vienna done so, this would have made it far more difficult for Bismarck to create war.
Italy was at first reluctant to ally with Prussia in fear that Prussia might lose. So anxious for war was Napoleon, however, that he guaranteed Italy Venetia no matter the outcome. On April 8, 1866, Prussia and Italy concluded an offensive alliance against Austria in which Italy insisted that the war had to occur within three months.
On June 12 with war between Prussia and Austria apparently inevitable, Austria concluded a secret treaty with France. In return for a pledge by Napoleon III to work to ensure Italian neutrality, Austria agreed to cede Venetia to France, which would then cede it to Italy, no matter the war’s outcome. In the event of an Austrian victory, Vienna would consult with Napoleon III on any major changes in Germany. Austria also made a verbal promise not to oppose the creation of a new French dominated state along the Rhine.
Bismarck now worked to create the war. Casting himself as a good liberal, he ordered the Prussian representative to the Diet of the German Confederation at Frankfurt to demand that the body be abolished and a new German political entity based on universal manhood suffrage be created without the participation of Austria. The thrust of this, of course, was to bring on war.
Both sides commenced military mobilization, and Austria foolishly allowed its governor of Holstein on June 6 to call its Diet into session to discuss the future of the duchy. Bismarck denounced this as contrary to the Convention of Gastein and ordered Prussian troops into the duchy. On June 14 on the motion of Austria, the Diet of the German Confederation at Frankfurt voted for war against Prussia for the latter’s invasion of Holstein. The vast majority of the German states, including Bavaria, Hanover, and Saxony, sided with Austria. Prussia declared this a violation of the federal constitution and also declared the German Confederation to be at an end.
Course of the Austro-Prussian War (1866)
Although the war also involved Italy, it is generally referred to as the Austro Prussian War or, for its duration, the Seven Weeks’ War. Bismarck intended it to be short. Fighting occurred in three theaters: Germany, Bohemia, and Italy.
Chief of the Prussian General Staff General von Moltke sought to make maximum use of the railroad and telegraph to strike quickly and catch his opponents by surprise. Austria, meanwhile, had done little to prepare for a two-front war that would involve Italy, which declared war on June 20.
With the south German states slow to mobilize, Moltke sent General Vogel von Falkenstein’s 40,000-man West Army against Hanover’s 19,000-man army under King George and General Alexander von Arentschildt before it could link up with the Bavarian Army. The West Army entered Hanover and converged on the Hanoverians at Langensalza (Bad Langensalza) from the south, west, and north.
Eager for glory, General Eduard Flies, commanding the southern Prussian force, disregarded Moltke’s orders and attacked prematurely on June 27 before the other Prussian forces could arrive. Flies’s men were badly mauled by the Hanoverians and were forced to withdraw in disorder. This victory went for naught, however, as the next day the other Prussian corps arrived, and on June 29 Hanoverian king George was forced to surrender at Nordhausen. The Prussians disarmed the Hanoverians and sent them home.
Meanwhile, the bulk of the German forces were moving southward against the Austrians, placed by intelligence reports concentrating northwest of Olmütz (present-day Olomouc in the Czech Republic). Moltke utilized the railroad to move and the telegraph to coordinate three separate Prussian armies. Prussian king Wilhelm I had nominal commands. The Army of the Elbe, under General Karl Herwarth von Bittenfeld, occupied Dresden in Saxony on June 19, then moved to join the First Army under Prince Friedrich Karl to enter Bohemia via passes in the Erzgebirge and Riesengebirge during June 22-23. Meanwhile, the Second Army under Crown Prince Friedrich moved south through Silesia.
At Münchengrätz on June 28, the Army of the Elbe and the First Army joined to defeat retreating Saxon troops under Prince Albert and the Austrian I Corps under General Count Eduard Clam-Gallas. The Prussians suffered 341 casualties and inflicted some 2,000 (1,400 of them prisoners). There was also fighting at Burkersdorf, Rudersdorf, and Skalice (Skalitz).
Austrian General Ritter Ludwig August von Benedek commanded the Austria North Army and allied Saxon forces in Silesia. An incompetent strategist whose military experience was confined to Italy, he had never before commanded large numbers of troops. Meanwhile, the far more capable Field Marshal Archduke Friedrich Rudolf Albrecht was assigned command of Austrian forces in Italy, where the House of Habsburg was most likely to be victorious.
On July 2, Moltke learned that Benedek’s North Army was concentrating along the upper Elbe, north of Königgrätz (today Hradec Kralové). The Austrians were within striking distance of two of Moltke’s armies, Bittenfeld’s Army of the Elbe and Prince Friedrich Karl’s First Army. In numbers of men, the two sides were about equal. Moltke commanded about 221,000 men and 702 guns, while Benedek commanded some 206,000 men (184,000 Austrians and 22,000 Saxons) and 650 guns. The Prussians had a distinct advantage in small arms, however. Their Dreyse breech loading needle gun could fire six times as fast as the Austrian Lorenz muzzle-loader.
Moltke, who was in contact with all three of his advancing armies by telegraph, attempted a double envelopment. That night, however, the telegraph link with Crown Prince Friedrich’s Second Army broke down. Moltke nonetheless decided to proceed with the other two armies and sent a courier to ride the 20 miles to the crown prince to tell him to bring up his army as soon as possible.
Cavalry engagement at the battle of Königgrätz (Alexander von Bensa, 1866).
The ensuing Battle of Königgrätz (Hradec Kralové), also known as the Battle of Sadowa (Sadova), was the largest European land battle until World War I. The Army of the Elbe and the First Army at tacked in a pouring rain at dawn on July 3. Crowded onto too narrow a front, they thus were ideal targets for the Austrian artillery but were saved only by foolish Austrian bayonet counterattacks, which forestalled the artillery and brought little result. Nonetheless, by 11:00 a. m. the Austrians had blunted the Prussian attacks. Benedek might have won the day had he committed his cavalry, but he refused. At about 1:30 p. m., the Prussian Second Army at last arrived and fell on the Austrian northern line, quickly reversing the situation. Benedek ordered a retreat, covered by his artillery. Moltke did not pursue.
Austrian and Saxon losses were nearly five times those of Prussia. The Prussians sustained some 9,000 casualties (1,900 killed, 6,800 wounded, and 275 missing). Austrian and Saxon losses were roughly 44,000 (5,735 killed, 8,440 wounded, some 22,000 prisoners, and 7,925 missing). Austria also lost 116 guns. The battle was decisive. With its heavy losses, on July 22 Vienna had no choice but to agree to an armistice on Prussian terms.
To the south, the Italian strategic plan called for an invasion of Austrian Venetia along the Mincio and Po Rivers by 200,000 men and 370 guns, defended by Archduke Albrecht’s Austrian South Army, with only 75,000 men and 168 guns. The critical battle of the campaign occurred at the old battlefield of Custoza, southwest of Verona. In a major tactical blunder, Italian commander General Alfonso Ferrero di La Marmora, who was unaware of the South Army’s strength and dispositions, managed to get only 65,000 troops and 122 guns across the Mincio before they were confronted by virtually the entire Austrian South Army.
In the daylong Battle of Custoza on June 24, the Austrians defeated the Italians piecemeal, with the Austrian Light Cavalry Brigade playing the major role and the Italians driven back across the Mincio into Lombardy. Albrecht did not pursue. The Italians suffered 3,800 killed or wounded and 4,300 taken prisoner. Austrian casualties were 4,600 killed or wounded and 1,000 missing. Despite the outcome of the battle, on July 3 Napoleon III arranged the transfer of Venetia to France, then ceded it to Italy.
Given command of 10,000 men and a flotilla on Lake Garda, Italian general Giuseppe Garibaldi fought a series of small, indecisive engagements with the Austrians during July 3-21. He was about to attack Trent when he was ordered to withdraw. Bismarck made it clear to the Italian government that it would not be allowed to se cure part of the Trentine Tyrol.
The only sea battle of the war was at Lissa in the Adriatic on July 20, between virtually the entire Italian and Austrian Na vies. Commanders proved important. The incompetent Admiral Count Carlo Pel lion di Persano commanded the Italians; capable young rear admiral Wilhelm von Tegetthoff had charge of the Austrian side. Persano sortied on July 15. He proceeded not to Pola, where the Austrian fleet was located, but against the Austrian island of Lissa. For two days the Italians bombarded Lissa with little effect. Persano was landing men there when informed of the Austrian approach. Tegetthoff had 21 ships, Persano 31. Each side had a half dozen ironclads. Tegetthoff immediately attacked and won the battle, with the Italians withdrawing. The Italians lost 2 ships; 4 others were badly damaged (1 of which subsequently sank). They also suffered 619 dead and 39 wounded. The Austrians had only several ships damaged and 38 men killed and 138 wounded. The Battle of Lissa was the first between oceangoing ironclad fleets at sea and the only major fleet encounter between ironclads in which the principal tactic was to ram the opposing vessel.
On July 5 a badly shaken Napoleon III had offered his good offices to end the war. Bismarck accepted on condition that the terms of peace were agreed to before any armistice was concluded. Napoleon, ill and his army unready to intervene, agreed to the Prussian terms imposed in the Preliminary Peace of Nikolsburg in southern Moravia on July 26. Prussia annexed the states of Hanover, Hesse-Kassel, and Nassau as well as the free city of Frankfurt. The German Confederation was abolished, and Austria was excluded from German affairs. Prussia then reorganized Germany north of the Main River into the North German Confederation under its leadership. The south German states of Bavaria, Baden, and Württemberg remained independent. King William I wanted an indemnity, a parade in Vienna, and additional territory from Austria, but Bismarck set himself against this and won his point. Austria retained all its territory, and there was no indemnity. The August 23 Peace of Prague merely confirmed these terms.
The long struggle between Prussia and Austria for mastery in the Germanies, which began with the War of the Austrian Succession in 1740, was over. Prussia now dominated Germany.