Wikipedia (consulted 3/06/2013)
The Master of Castelsardo was an Italian painter active in Sardinia at the end of the 15th and the beginning of the sixteenth century. His name comes from a painting of the Madonna and Child currently in the cathedral of Castelsardo.
His influence appears to be primarily Catalan and he perhaps started painting in Barcelona around 1490; some scholars have identified him with Gioacchino Cavaro, though others dispute this. His other works included the retablos in the church of St. Peter at Tuili (executed between 1489 and 1500), in the church of Santa Rosalia at Cagliari, the Trinity Retablo (like the previous one, originally commissioned for the Frasciscan convent at Tallano, in Corsica, now in the basilica of Saccargia).
Antonio Corona-Alcalde (corona2004-1) suggests that he may be Pablo Vergós (c.1465-1495), and refers to postHSP, vol. 7, part 2, pp. 445-447. On the other hand, recent Italian scholarship has not pursued the possibility but looked to identify the Master. Aru suggests the possibility that he was Gioacchino Cavaro [Carlo Aru, Il maestro di Castelsardo, Annali della Facoltà di Lettere e Filosofia della R. Università di Cagliari, Cagliari, 1926-27.] (wikipedia 13/01/2009).