According to the modern papal historian Gaetano Moroni, he was consecrated a cardinal by Pope Urban II in 1088, but a bishop John is still recorded at Porto as late as 18 February 1095.
Moroni, following Ferdinando Ughelli, also records that Maurice consecrated an altar dedicated to Saint Mammes in the church of Santa Cecilia in Trastevere on 24 February 1098.
The earliest conclusive attestation of Maurice as bishop comes from the Liber pontificalis, which records him among the six cardinal-bishops who on 14 August 1099 consecrated Pope Paschal II.
[1] On 4 May 1100, Paschal appointed Maurice as his legate to the Holy Land, responsible for bringing the church in the new Crusader states more firmly under papal control.
According to Albert of Aachen, whose account is based on reports, the legate forbade Daimbert from officiating at the celebration of Easter and Maurice himself led the ceremonies.