 Simplician was asked to judge some doctrinal statements by the Council of Carthage (397) and by the First Council of Toledo.He also consecrated Gaudentius of Novara a bishop, and according to the 13th-century writer Goffredo of Bussero, he organized the texts of the Ambrosian liturgy.Simplician's feast day was anciently set on 15 August, together with the feast of the translation to Milan of the relics of Sisinnius, Martyrius and Alexander; so his death was deemed to have been on 15 August 400; but probably Simplician died between the end of 400 and the first half of 401.