Carew obtained leave of the queen to prosecute his claims and sailed for Ireland from Ilfracombe in August 1568. His first proceedings were against Christopher Cheevers for possession of the lordship of Maston in County Meath; Carew claimed he couldn't get a fair trial at common law before a jury and went instead before the lord deputy, Sir Henry Sidney, sitting in council, whereupon Cheevers agreed to a compromise of the claim. Then he secured a decree of Sidney and council for the barony of Idrone in County Carlow, which was then in the possession of the Kavanagh clan, and was appointed captain of Leighlin castle (in succession to Sir Thomas Stukley) in the centre of the barony.