When
Spain entered the
American Revolutionary War in 1779,
Bernardo de Gálvez, the energetic governor of
Spanish Louisiana, immediately began offensive operations to gain control of
West Florida beginning with his assault at
Fort Bute. In September 1779 he gained control over the lower
Mississippi River by
capturing Fort Bute and then shortly thereafter obtaining the surrender of the remaining forces following the
Battle of Baton Rouge. He followed up these successes with the
capture of Mobile on March 14, 1780, after a brief siege. Gálvez began planning an assault on
Pensacola, West Florida's capital, using forces from
Havana with the recently captured Mobile as the launching point for the attack. British reinforcements arriving in Pensacola in April 1780 delayed the expedition, however, and when an invasion fleet finally sailed in October it was dispersed by
Solano's Hurricane a few days later. Gálvez spent nearly a month regrouping the fleet at Havana.
British defenses Following the outbreak of hostilities with Spain in 1779, General
John Campbell, concerned over the condition of the defenses, requested reinforcements and began construction of additional defenses. By early 1781 the Pensacola garrison consisted of the
16th Regiment, a battalion from the
60th, and
7 (Johnstones) Company of the 4th Battalion Royal Artillery (Present day
20 Battery Royal Artillery,
16 Regiment Royal Artillery). These were augmented by the Third Regiment of
Waldeck and the Maryland Loyalist Battalion, as well as the Pennsylvania Loyalists. These troops were provincial soldiers rather than
militia. Gálvez had received detailed descriptions of the state of the defenses in 1779, when he sent an aide there ostensibly to discuss the return of escaped slaves, although Campbell had made numerous changes since then. Pensacola's defensive works in early 1781 consisted of
Fort George, an earthen works topped by a
palisade that was rebuilt under Campbell's directions in 1780. North of the fort he had built the Prince of Wales
Redoubt, and to its northwest was the Queen's Redoubt, also built in 1780. Campbell erected a battery called
Fort Barrancas Colorada near the mouth of the bay.
Spanish forces Gálvez embarked his flag with the Spanish fleet, under the command of Captain José Calvo de Irazabal. With about 1,300 men, the regular troops included a
Mallorcan regiment and
Arturo O'Neill commanding 319 men of Spain's Irish
Hibernia Regiment, and including militias of biracial and free Afro-Cubans. Gálvez had also ordered additional troops from New Orleans and Mobile to assist. The Spanish expeditionary force sailed from Havana on February 13. Arriving outside
Pensacola Bay on March 9, Gálvez landed some troops on
Santa Rosa Island, the
barrier island protecting the bay. O'Neill's Hibernians landed at the island battery, which he found undefended, and set up artillery which he used to drive away the British ships taking shelter in the bay. However, bringing the Spanish ships into the bay turned out to be difficult, just as it had been the previous year at the capture of Mobile. Supplies were offloaded onto Santa Rosa Island to raise the draft of some of the ships, but Calvo, the fleet commander, refused to send any more ships through the channel after the lead ship, the 64-cannon
San Ramon, grounded in its attempt. Furthermore, some British guns seemed to have the range to fire on the bay's entrance. Gálvez used his authority as governor of Louisiana to commandeer the ships that were from Louisiana. He boarded the
Gálveztown, and on March 18 he sailed her through the channel and into the bay. The three other Louisiana ships followed him, under what proved to be ineffective British artillery fire. After sending Calvo a detailed description of the channel, his captains all insisted on making the crossing, which they did the next day. Calvo, claiming that his assignment to deliver Gálvez' invasion force was now complete, sailed back to Havana in the
San Ramon. ==Siege==