Popes have always highlighted the inner link between the Virgin Mary as Mother of God and the full acceptance of Jesus Christ as Son of God.[214][215] Since the 19th century, they were highly important for the development of mariology to explain the veneration of Mary through their decisions not only in the area of Marian beliefs (Mariology) but also Marian practices and devotions. Before the 19th century, Popes promulgated Marian veneration by authorizing new Marian feast days, prayers, initiatives, the acceptance and support of Marian congregations.[216][217] Since the 19th century, Popes begin to use encyclicals more frequently. Thus Leo XIII, the Rosary Pope issued eleven Marian encyclicals.