When Spain entered the War in 1779, Bernardo de Gálvez, the energetic governor of Spanish Louisiana, immediately began offensive operations to gain control of British West Florida beginning with his assault at Fort Bute. In September 1779 he gained complete 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.