Liturgical reforms of Pope Pius XII
The liturgical reforms of Pope Pius XII took place mostly between 1947 and 1958. == Background == The celebration of the resurrection of Jesus Christ has been celebrated since the 2nd and 3rd century as Vigil, that is, night watch, celebrated on the night of Easter Sunday, from which the name Easter Night or Easter Vigil derived.
Source: Wikipedia — Liturgical reforms of Pope Pius XII (CC BY-SA 4.0)