Pope Francis has cracked down on the spread of the old Latin Mass, reversing one of Pope Benedict XVI's signature decisions in a major challenge to traditionalist Catholics.
Francis reimposed restrictions on celebrating the Latin Mass that Benedict relaxed in 2007.
The pontiff said he was doing so because Benedict's reform had become a source of division in the Roman Catholic Church and was being used as a tool by Catholics opposed to the Second Vatican Council, the 1960s meetings that modernised the church.
Francis issued a new law requiring individual bishops to approve celebrations of the old Mass, also called the Tridentine Mass, and requiring newly ordained priests to receive explicit permission to celebrate it from their bishops in consultation with the Vatican.
The move is likely to create an uproar among traditionalists already opposed to Francis' more progressive bent and still nostalgic for Benedict's doctrinaire papacy.