Not least the nobility of the sword was the nobles of the robe, Peter D'Agostino Rational Master of the Kingdom of Sicily, in the second half of the fifteenth century.

These Distinguished members of the D'Agostino entered the Court of the Real Estate, collegial office, having control functions, recording and jurisdiction on financial and monetary matters, composed of six rational masters appointed by the King.

These were the supervision of all financial affairs and accounts of all the other pecuniary officers, they participated in the meetings of the Holy Royal Council with binding opinion on their subject, and often corresponded directly with the sovereign without going through the viceroy.

Other positions held were: that of Governor Peter covered in Mazara, to Secreto by Philip Matthew, that of Ambassador William in Nicosia and in the Court of the Aragonese King Peter of Aragon, that of Governor of Pietro Bianchi Company in Palermo for several years, that of Magistrate John, that of Judge Pretoriano covered with James in Girgenti, that of Mazara del Castellano Crown Castle from Andreotto, that of Magistrate John, to Proconservatore Antonio, to Juror covered with Giovan Vincenzo, Matteo, Giovanni, and so on.

Mugnos in accordance with Inveges identifies the lineage derived from a Francesco D'Agostino lived in the thirteenth century in Palermo.