After the Break of Dromore on 14 March, Richard Hamilton's Jacobite forces had swept through Eastern Ulster bringing all of County Down and Antrim under their control. Carrickfergus and its surrounding area were securely under Jacobite rule as Hamilton advanced to lay siege to Derry, one of the few remaining Protestant strongholds in Ireland. What had initially seemed as though it would be a quick victory began to drag out through the summer, particularly as some Jacobite forces had to be diverted to confront the defenders of Enniskillen. Meanwhile, a series of relief forces were being prepared in England. Percy Kirke led an expedition to Derry, where the siege was finally broken on 28 July. In the face of the sudden defeat, Jacobite forces began to withdraw from Derry and employed a scorched earth policy as they retreated.