During the Dardanelles Operation Military_operation in September 1806 , Britain pressured Convincing Sultan Selim III to expel Extradition Sebastiani , declare Expressing_publicly war Hostile_encounter on France , cede the Danubian Principalities to Russia , and surrender Surrendering the Ottoman fleet , together with the forts on the Dardanelles , to the Royal Navy .

The war started Process_start in the Balkans in July 1853 , when Russian troops occupied Control the Danubian Principalities ( now part of Romania ) , which were under Ottoman suzerainty , then began Process_start to cross the Danube .

The conflicts were triggered Causation by the constant Dacian threat on the Danubian province of Moesia and also by the increasing need for resources of the economy of the Empire .