The Catholic Church engaged in a comprehensive process of reform following the Second Vatican Council (1962–65).[241] Intended as a continuation of Vatican I, under Pope John XXIII the council developed into an engine of modernisation.[241][242] It was tasked with making the historical teachings of the Church clear to a modern world, and made pronouncements on topics including the nature of the church, the mission of the laity and religious freedom.[241] The council approved a revision of the liturgy and permitted the Latin liturgical rites to use vernacular languages as well as Latin during mass and other sacraments.[243] Efforts by the Church to improve Christian unity became a priority.[244] In addition to finding common ground on certain issues with Protestant churches, the Catholic Church has discussed the possibility of unity with the Eastern Orthodox Church.[245] And in 1966, Archbishop Andreas Rohracher expressed regret about the 18th century expulsions of the Salzburg Protestants from the Archbishopric of Salzburg.