Start of the Great Siege of Gibraltar

Background. Britain had stepped up preparations after France entered the American conflict in 1778, but the French initially prioritised sending forces to America. Only when Spain joined the war did the long-expected siege commence. Spain entered on the French side with the primary war aim of wresting Gibraltar from the British.

Command and Garrison. George Augustus Eliott, 1st Baron Heathfield, a British Army officer, had been appointed Governor of Gibraltar on 25 May 1777, succeeding acting governor Robert Boyd. In 1778 the garrison numbered 5,382 soldiers under Eliott as Governor-General, and he would lead it throughout the siege.

Outbreak of the Siege. On 16 June 1779 Spain issued what amounted to a declaration of war against Great Britain, and a blockade of Gibraltar commenced at once. The siege of the garrison began in June–July 1779 and would ultimately last until 1783, during the American War of Independence.

Early Operations. In July 1779 Gibraltar was besieged by the French and Spanish. On 6 July 1779 an engagement occurred between British ships and Spanish vessels bringing supplies to Spanish troops ashore. By August the Spanish intent to starve the garrison was evident, and Eliott applied his engineering skills to improving the fortifications.