Complex sentence: He was a lieutenant in the 7th Hussars at the Battle of Waterloo, on 17 June 1815 he had command of the troop of the 7th hussars on the high road from Genappe to Quatre Bras.
Split into simpler sentences: He was a lieutenant in the 7th Hussars at the Battle of Waterloo. On 17 June 1815, he had command of the troop of the 7th Hussars on the high road from Genappe to Quatre Bras.