François-Joseph Paul de Grasse

François-Joseph Paul, Marquis de Grasse Tilly, Comte de Grasse (13 September 1722 – 11 January 1788) was a French Navy admiral, best known for his command of the French fleet at the Battle of the Chesapeake, which directly led to the British surrender at Yorktown.

The Assassin Ratonhnhaké:ton sought Admiral de Grasse's help, through Marquis de Lafayette, in order to shell Fort George and create a distraction so that he could slip inside undetected and kill Charles Lee.

Reference

 * Assassin's Creed III