[1] In 1862, the head of the Austrian Navy, Archduke Ferdinand Max, argued for a major construction program as part of the Austro-Italian ironclad arms race.

The Austrian Reichsrat (Imperial Council) refused to grant funding for the program, but Kaiser Franz Joseph intervened and authorized the navy to place orders for the work anyway.

[3] After returning to service, Schwarzenberg, the screw frigate Radetzky, and the gunboat Seehund were deployed to Greek waters in 1863 during a period of instability in the country resulting from the expulsion of Otto of Greece.

At the time, the Danish fleet was far superior to the Prussian naval forces initially available, which allowed the Danes to blockade the German coast.

To assist the Prussians, the Austrian Navy sent Kommodore (Commodore) Wilhelm von Tegetthoff with Schwarzenberg, Radetzky, and Seehund to break the Danish blockade, as these ships were still at sea in the Levant, and thus were ready to sail.

[5][6][7] On the morning of 9 May, Tegetthoff learned that a Danish squadron consisting of the steam frigates Niels Juel and Jylland and the corvette Hejmdal were patrolling off the island of Heligoland.

After Schwarzenberg caught fire, Tegetthoff broke off the action and escaped to the neutral waters around Heligoland, where the ships remained until early the next day.

Though the Danish squadron had won a tactical victory at Heligoland, the arrival of Austrian warships in the North Sea forced the Danes to withdraw their blockade.

As the fleet made its preparations, the ships carried out extensive practice in the Fasana Channel, which was protected from an Italian attack by naval mines.

Schwarzenberg and the other wooden vessels were fitted with iron chains that draped down over the sides of their hulls to give them a degree of protection for the coming fight with Italy's larger fleet of ironclad warships.

Tegetthoff initially believed the attack to be a feint to draw his fleet away from Venice and Trieste, but by the 19th, it had become clear that the Italians intended to land on the island.

Petz then took his ships south to attack the Italian wooden frigates, which had failed to answer Persano's orders.

Over the course of 1868, he instituted a series of reforms to improve efficiency in the fleet, which included removing Schwarzenberg and Adria from active status, as they were no longer particularly seaworthy.