The Codex of Guardiagrele contained several pieces composed by artists from the Abruzzo and from other regions which worked in Guardiagrele at the church of Santa Maria Maggiore. These compositions clearly show that the musical production of polyphonic works was rich in this region. As A. Ziino, G. Cattin and O. Mischiati explain: “The compositions of Guardiagrele are an evidence that fifty years earlier the polyphony was a common practice even in small towns of the Abruzzo; they were the first real document of the diffusion of polyphonic mensural music in the central – southern Italy”. The Codex is composed by several compositions of the early 1400 kept into mauscript of liturgic missals conserved until 1979 in Guardiagrele (in the province of Chieti). They are a gradual and an anthiphonary of three and four volumes respectively and a psalter, all written on a parchment arranged in folio of great dimensions. An ephigraph written on the salterio assigns a date at the manuscript: 1410 (“Incipit ordo Psalterii secundum ordinem sancte Romane Ecclesie pro ecclesia Sancte Marie de Guardia Grelis ad petitionem Simonis Cichi Jacobi Gentilis MCCCCX”).