"Sacrosanctum Concilium" is the cornerstone of the reform of the Catholic Liturgy in the 20th century. By the middle of the 20th century, it was already clear that the liturgical celebration had become less connected to the life of the people: speeches and rituals in Latin, people participating... Catechism on the history of liturgical doctrine in the Second Vatican Council, with P. Randriamanamahenina Robert Marie.