An episcopal conference, sometimes called a conference of bishops, is an official assembly of the bishops of the Catholic Church in a given territory. Episcopal conferences have long existed as informal entities. The first assembly of bishops to meet regularly, with its own legal structure and ecclesial leadership function, is the Swiss Bishops' Conference, which was founded in 1863. More than forty episcopal conferences existed before the Second Vatican Council. Their status was confirmed by the Second Vatican Council and further defined by Pope Paul VI's 1966 motu proprio, Ecclesiae sanctae.