Complex sentence: During the Austro-Prussian War of 1866, Henk was commander of the Prussian North Sea Fleet, and in 1867 was promoted to the rank of "Kapitän zur See" (Captain at Sea).
Split into simpler sentences: During the Austro-Prussian War of 1866, Henk was commander of the Prussian North Sea Fleet. In 1867 was promoted to the rank of "Kapitän zur See" (Captain at Sea).