The church of St. Matteo ad Ysclam, belonging to the Cistercians of St. Pastore, was entrusted by the Preacher Fathers to the confraternity of the Merchants of Rieti. It was named after St. Peter from Verona after the Apostolic Visitor Monsignor Pietro Camaiani, in 1574, denounced the failure of the decoration of
the Oratory set up in the new cloister of the conventual complex of St Domenico to comply with the dictates of the Tridentine Decrees concerning sacred art. The confreres willingly adhered to the proposal, but they re-adapted the recently built travertine portal to the facade of the new building and commissioned the best artists of the time to decorate the church in which the title of St. Pietro Martire was transferred.
Ascanio and Vincenzo Manenti created excellent quality frescoes and canvases.