In contrast, the revision by Pope Pius XII, though limited to the liturgy of only five days of the Church's year, was much bolder, requiring changes even to canon law, which until then had prescribed that, with the exception of Midnight Mass for Christmas, Mass should not begin more than one hour before dawn or later than one hour after midday. In the part of the Missal thus thoroughly revised, he anticipated some of the changes affecting all days of the year after the Second Vatican Council. These novelties included the first official introduction of the vernacular language into the liturgy for renewal of baptismal promises within the Easter Vigil celebration.