Thomas Mathews had had a solid but unspectacular career as a naval captain, rising to command a small squadron before retiring from the navy in 1724. He returned to naval service in 1736, but only in a shore-based administrative role. The outbreak of war with Spain and the imminent threat of war with France led to Mathews' return to active service after years of effective retirement, with a promotion directly to Vice-Admiral of the Red on 13 March 1741. He was given command of a fleet in the Mediterranean, and with it an appointment as plenipotentiary to Charles Emmanuel III, King of Sardinia (who supported Maria Theresa's claim), and the other courts of Italy. The choice of Mathews for the role was somewhat unexpected, as he was not especially distinguished, and had not served in the navy for a number of years.