[2][3] Fort Shirley is located on a peninsula just north of Portsmouth, in an area known as Prince Rupert's Head.

[2] The British began Fort Shirley's construction in 1765 as a garrison to defend north Dominica.

It consisted of more than 50 buildings,[6][2] including seven gun batteries, seven cisterns, powder magazines, and ordnance storehouses, as well as barracks that could house over 600 men.

[8][9] African soldiers, who were recruited as slaves and stationed at Fort Shirley, mutinied and took over the garrison for three days.

[10][2] The revolt influenced the Mutiny Act 1807,[2][11] under which all serving soldiers recruited as slaves in the West India Regiments of the British Army were freed.