In September 1806, the British government pressured Sultan
Selim III to expel Sebastiani, declare war on France, cede the
Danubian Principalities to Russia, and surrender the Ottoman fleet, together with the forts on the Dardanelles, to the
Royal Navy. After Selim's rejection of the ultimatum, a British squadron under Vice Admiral
John Thomas Duckworth entered the Dardanelles on 19 February 1807 and destroyed an Ottoman naval force in the
Sea of Marmara, and anchored opposite
Constantinople. With French assistance the Ottomans erected powerful batteries and strengthened their fortifications. The British warships were cannonaded suffering the loss of two ships. Duckworth made the decision to withdraw to the Mediterranean on 3 March 1807. ==Alexandria expedition of 1807==