The research aims to get a better knowledge concerning some issues related to first patrons of Carlo Crivelli in the Marche. In particular this research examines a dossier on the polyptych painted by Carlo Crivelli for the church of Porto San Giorgio in 1470, and kept at Fondazione Zeri. This document folder was sent to Federico Zeri just some months earlier his death from the Countess Gladys Salvadori’s daughter. The dossier provides a memorandum with some lines of agreement for a work, which sometimes scholars put in relationship with the polyptych of 1470, but without any proof. Indeed art historians believed that some information of the memorandum are related to the polyptych for Porto San Giorgio. According to a legend, this painting was commissioned by Giorgio da Prenta, an Albanian soldier, but the analysis of the typewritten document held at Fondazione Zeri has permitted to relate these archival records to the altarpiece painted by Carlo Crivelli for the Domenican church of Fermo in 1472.