Complex sentence: Milne became Commander-in-Chief, North America and West Indies Station in January 1860, and having been appointed Knight Commander of the Order of the Bath (Military) on 20 February 1864, he was promoted to vice-admiral on 13 April 1865.
Split into simpler sentences: Milne became Commander-in-Chief, North America and West Indies Station in January 1860. He was appoinred Knight Commander of the Order of the Bath (Military) on 20 February 1864 and was promoted to vice-admiral on 13 April 1865.