In 1840 Stirling was given command of and instructions to join the Mediterranean Fleet. The British Foreign Secretary, Lord Palmerston, considered it was necessary to show a strong British naval presence in the Mediterranean. Muhammad Ali Pasha had triggered the Oriental Crisis of 1840 by declaring himself Khedive of Egypt, which had been until then a province of the Ottoman Empire. Also King Ferdinand II of the Two Sicilies and Naples, had been persuaded by a British naval blockade of Naples to restore to a British company the monopoly for Sicilian sulphur, an essential ingredient of gunpowder. The "Indus" reached Gibraltar in August 1841 and made herself felt along the Algerian coast on her way to the Mediterranean station at Malta. For a few months she was deployed around Sicily and the boot of Italy, but in November Stirling received new instructions to show a presence and monitor the situation at Lisbon. Portugal had been in turmoil for several years and the British Admiralty had received intelligence that Lisbon was threatened by a 5,000 strong revolutionary army and the Portuguese Government was preparing for conflict. Stirling was directed not to take part in any action, but to safeguard British subjects and the Portuguese royal family. In the event, the conflict was resolved peacefully.