 The Archdeacon is attested as early as 907, the Provost by 908, the Archpriest by 966, and the Primicerius by 929.On 23 December 1189, an agreement was reached between the Chapter of S. Vincenzo and the Chapter of S. Alessandro to unite as a single body of Canons.The arrangement was approved by Pope Clement III on 21 June 1190.