Not long after her commissioning, the hostilities of the Seven Years' War had escalated and spread to Europe, and in May 1756 Britain declared war on France of the Ancien Régime. "Dolphin" was pressed into service throughout the conflict, and was present at the Battle of Minorca in 1756 when a fleet under Admiral John Byng failed to relieve Port Mahon, Britain's main base in the Western Mediterranean (as a result of which Byng was later court-martialled and shot).