In 1984 Noel O’Regan demonstrated that Roman manuscripts containing Lasso’s motets were reworkings of motets found in published editions. This article reopens an investigation of the Roman manuscript motet books in the light of an autograph booklet by the Oratorian priest and censor of music Giovanni Giovenale Ancina (1599). This document contains two lists of motets, comprising a wide selection that reflects a search for variety in the number of voices (with a preponderance of eight-voice motets), age and style of the motet. It shows a large number of concordances with several manuscript anthologies related to the Oratorian circles. Ancina’s bookletallows us to propose new attributions for motets by Zoilo and Prospero Santini, better known as a chapel master. Finally, a comparison with existing sets of music books qualifies the multiple authorship of the motet in the Roman erudite milieu of that time.