In 1799 Napoleon, in pursuance of his scheme for raising a Syrian rebellion against Turkish domination, appeared before Acre, but after a siege of two months (March–May) was repulsed by the Turks, aided by Sir Sidney Smith and a force of British sailors. Having lost his siege cannons to Smith, Napoleon attempted to lay siege to the walled city defended by Ottoman troops on 20 March 1799, using only his infantry and small-calibre cannons, a strategy which failed, leading to his retreat two months later on 21 May.