He expanded the concept of purgatory and converted the Eucharist from a sacrament into a sacrifice for redemption, having value for the living and the dead. He officially approved the invocation of saints and martyrs and the use of relics and amulets to reduce temporal punishments. His view of Christ and the Trinity followed the decisions of the ecumenical councils. Gregory I . . . was largely responsible for the creation of the medieval papacy. Fourth, he was important for his writings. The Moralia,