 The treaty of Utrecht (1714), where he had been part of the Spanish delegation, decided for Sardinia to be part of the Austrian crown.Aftermath he was appointed as an envoy plenipotentiary at the republic of Genoa, from where he supported the attempt by cardinal Alberoni to re-conquer Sardinia to the Spanish crown.The island was actually conquered in 1717, but had to be left in 1720 (War of the Quadruple Alliance) and was acquired by the Dukes of Savoy.