Austria began early to arm, for she required longer time to mobilize her army. Prussia, on the contrary, was in readiness for action. Every Prussian who is twenty years old, without distinction of rank, has to serve in the army, three years with the colors, five more in the reserve, after which he is placed for eleven years in the Landwehr, and liable to be called out when occasion requires. In peace everything is kept ready for the mobilization of its army. In a wonderfully short time the organization was complete, and 260,000 men brought into the field in Bohemia. In arms, they had the advantage of the needle-gun. The Prussian forces were in three divisions, the "First Army" under the command of Prince Frederick Charles; the "Second Army" under that of the crown prince; and the "Army of the Elbe," under General Herwarth. The supreme command of the Austrian army of the north was given to Feldzeugmeister von Benedek, that of the south to the Archduke Albert.
On June 14, Prussia sent a telegraphic summons to Hanover, Hesse-Cassel, and Saxony, demanding them to reduce their armies to the peace establishment, and to concur with Prussia respecting the Germanic confederation; and that if they did not send their consent within twelve hours, war would be declared. The states did not reply, Prussia declared war, and on the 16th invaded their territories. The occupation and disarmament of Hanover and Hesse were necessary to Prussia for a free communication with her Rhenish provinces, and she effected her purpose by means of well-planned combinations, so that in the course of a few days these states were overrun by Prussian troops, and their sovereigns expelled.
The rapid progress of events, and the Prussian declaration of war, had taken Hanover by surprise. Her army was not yet mobilized; Austria had evacuated Holstein, or she could have looked to her for support. To attempt to defend the capital was hopeless; so King George, suffering from blindness, moved with his army to Gottingen, with a view of joining the Bavarians. Prussia entered by the north, and, assisted by her navy on the Elbe, was by the 22d in possession of the whole of Hanover. Closed round on all sides by the Prussians, unassisted by Prince Charles of Bavaria, Gotha having declared for Prussia, the king of Hanover, with his little army, crossed the frontier of his kingdom, and at Langensalza, fifteen miles north of Gotha, encountered the Prussians, and remained master of the battlefield. But victory was of little avail; surrounded by 40,000 Prussians, the king was forced to capitulate. The arms and military stores were handed over to the enemy, and the king and his soldiers allowed to depart. Thus, through the supineness of Prince Charles of Bavaria, a whole army was made captive, and Hanover erased from the roll of independent states.
More fortunate than his neighbor, the elector of Hesse-Cassel saved his army, though not his territory, from the invader. His troops retired toward the Maine, where they secured a communication with the federal army at Frankfort. The elector remained in Hesse, and was sent a state prisoner to the Prussian fortress of Stettin, on the Oder. The Prussians overran his territory, declaring they were not at war against "peoples, but against governments."
Two bodies of Prussian troops entered Saxony—the First Army and the Army of the Elbe—and the Saxon army retired into Bohemia to effect a junction with the Austrians. On the 20th, Leipzig was seized, and the whole of Saxony was in undisturbed possession of the Prussians; Prince Frederick Charles issuing a most stringent order that private property should be respected, and every regard shown to the comfort of the inhabitants. His order was strictly observed, and every measure taken to prevent the miseries attendant on the occupation of a country by a foreign army.
The invasion of Saxony brought immediately open war between Prussia and Austria, and on the 23d the Prussian army crossed the Bohemian frontier—only a week since it had entered Saxony. It is needless here to detail the battles which immediately followed; suffice it to say, the Prussians were victorious in all—at Podoll, where the needle-gun did such terrible work; Munchengratz, which gave them the whole line of the Iser; Trautenan, Gitschen, and others. On the 1st of July, the king of Prussia arrived from Berlin and took the supreme command of the army. The following day brought news from the crown prince that he was hastening from Silesia with the Second Army, whereby the whole of the Prussian forces would be concentrated. On the 3d of July was fought the decisive battle of Koniggratz, or Sadowa, as it is sometimes called, from the village of that name, a cluster of pine-wood cottages, enclosed by orchards, with a wood-crowned hill at the back, which was fiercely disputed by the contending parties.
On that day, General von Benedek had taken his position with the Austrian army in front of the frontier fortress of Koniggratz, on the right bank of the Elbe, about fifty-five miles east of Prague, to oppose the passage of the crown prince from Silesia. In his front lay the marshy stream of Bistritz, upon which Sadowa and a few other villages are situated. At half-past seven in the morning the battle began, and continued with great slaughter without any marked advantage on either side till the arrival of the crown prince decided, like the advance of Blücher at Waterloo, the fortune of the day. The Austrians were completely routed, and fled across the Elbe to save the capital. They lost 40,000 men in this sanguinary conflict, the Prussians 10,000. The forces in the field were 200,000 Austrians and Saxons, and 260,000 Prussians.
Immediately after her crushing defeat, Austria surrendered Venetia to France, and the Emperor Napoleon at once accepted the gift and gave it over to Victor Emmanuel.
On July 26, preliminaries of peace were signed at Nikolsburg, and peace was finally concluded at Prague, August 23, between Prussia and Austria, and about the same time with the South German states. The Prussian House of Deputies voted the annexation of the conquered states, and in October peace was concluded with Saxony. By these arrangements, Hanover, Hesse-Cassel, and Frankfort became provinces of Prussia, as well as the long-disputed duchies of Denmark. All the German states north of the Maine concluded a treaty, offensive and defensive, for the maintenance of the security of their states. Prussia increased her territory by 32,000 square miles and her population 4,000,000; and in October, 1866, the whole of northern Germany was united into a Confederation.
This Confederation, known as the North German, possessed a common parliament elected by universal suffrage, in which each state was represented according to its population. The first or constituent parliament met early in 1867, and adopted, with a few modifications, the constitution proposed by Count Bismarck. The new elections then took place, and the first regular North German parliament met in September, 1867. According to this constitution, there was to be a common army and fleet, under the sole command of Prussia; a common diplomatic representation abroad, of necessity little else than Prussian; and to Prussia also was intrusted the management of the posts and telegraphs in the Confederation.