Second Schleswig War was the 1864 invasion of Schleswig-Holstein by Prussia and Austria. At that time, The duchies were part of the Kingdom of Denmark. Rear-Admiral Wilhelm von Tegetthoff commanded a small Austrian flotilla which traveled from the Mediterranean Sea to the North Sea. On May 9, 1864, Tegetthoff commanded the Austrian naval forces in the naval action off Heligoland from his flagship, the screw-driven . The action was a tactical victory for the Danish forces. However, in strategic sense the Austro-Prussian fleet succeed breaking the Danish blockade. It was also the last significant naval action fought by squadrons of wooden ships and the last significant naval action involving Denmark. Third Italian War of Independence On 20 July 1866, near the island of Vis (Lissa) in the Adriatic, the Austrian fleet, under the command of Rear-Admiral Wilhelm von Tegetthoff, made its name in the modern era at the Battle of Lissa during the Third Italian War of Independence. The battle pitted Austrian naval forces against the naval forces of the newly created Kingdom of Italy. It was a decisive victory for an outnumbered Austrian over a superior Italian force, and was the first major European sea battle involving ships using iron and steam, and one of the last to involve large wooden battleships and deliberate ramming. Peacetime In 1873 the new sail and steam frigate (crew 480) was added to the fleet, which took part in the International Naval Review off Gruž in 1880. During peacetime, Austrian ships visited Asia, North America, South America, and the Pacific Ocean. In 1869 Emperor Franz Joseph travelled on board the screw-driven corvette SMS Viribus Unitis (not to be confused with the later battleship of the same name) to the opening of the Suez Canal. The ship had been named after his personal motto. Polar Expedition Austro-Hungarian ships and naval personnel were also involved in Arctic exploration, discovering Franz Josef Land during an expedition which lasted from 1872 to 1874. Led by the naval officer Karl Weyprecht and the infantry officer and landscape artist Julius Payer, the custom-built schooner Tegetthoff left Tromsø in July 1872. At the end of August, she got locked in pack-ice north of Novaya Zemlya and drifted to hitherto unknown polar regions. It was on this drift when the explorers discovered an archipelago which they named after Emperor Franz Joseph I. In May 1874 Payer decided to abandon the ice-locked