Sisnando continued in the service of Ferdinand's successor, Alfonso VI. In March 1075 Sisnando was at Oviedo with the king—his first appearance at court—and El Cid for the opening of the Arca Santa. Later that same month he was one of many judges in a case between the bishop of Oviedo and count Vela Ovéquiz concerning the property of the monastery of San Salvador de Tol, though only he and El Cid signed the decision. Later in the year Sisnando was the principal leader of Alfonso's expedition against Seville and Granada. He took part in the expedition against Granada in 1080 as well.