This beauty of a ship is the Panzerfregatte (armoured frigate), later Panzerschiff (armoured ship), then Großer Kreuzer (large cruiser) König Wilhelm. She was laid down at the Thames Iron Works Blackwell as Turkestan (later changed to Fatih) for the Ottoman Empire, but was purchased by the Prussian navy and launched 25 April 1868. With 18 x 9.4" guns (later increased to 22, and 1 x 5.9" and 18 x 3.4" added), she was one of the most powerful warships in the world and she was also a nice 14.7 kn fast.

On joining the fleet, she was made flagship of the Panzergeschwader (armoured ship squadron) and flew the flag of Prinz Adalbert. In the Franco-Prussian war of 1870/71 she was the flagship of the fleet commander, VAdm. Jachmann.

On 31 May 1878, off Dover, while trying to make way for two British sailing vessels, she rammed and sank the Panzerfregatte Großer Kurfürst, of whose crew 269 drowned. (What happened actually is that both ship sailing on parallel courses just 100 yards apart turned to starboard, and then after having passed the sailing ships turned back to port, but König Wilhelm, being the much larger ship--you know how those battlewagons turn!--didn't react to the helm quite as fast as did the smaller Großer Kurfürst.) The Panzerschiff was heavily damaged and did not return to active service before 1887.

In 1896 she was rebuilt as large cruiser and continued to serve as squadron flag for some years. In 1904 she was made a harbour ship, but returned to the fleet as school ship in 1907 in which capacity she served through the Great War in Flensburg-Mürwik. She was sold on 4 January 1921. Only the Aviso Grille ever served the German fleet longer than the 59 years König Wilhelm did.