Schleswig-Holstein Question
Hornby became commanding officer of the first-rate HMS "Neptune" in the Mediterranean Fleet in February 1861 and then became flag captain to the Commander-in-chief, Channel Squadron in the second rate HMS "Edgar" in May 1863. In January 1864 the squadron was instructed to shadow the ships of the Austro-Hungarian Navy en route to Prussia and to sink their ships if they bombarded Copenhagen as their answer to the Schleswig-Holstein Question.