The Eastern Catholic Churches are autonomous (in Latin, sui iuris) particular Churches in full communion with the Bishop of Rome—the pope. They preserve the centuries-old liturgical and devotional traditions of the various Eastern Christian Churches with which they are associated historically. While doctrinal differences divide these other Eastern Christian Churches into groups not in communion with one another, the Eastern Catholic Churches are united with one another and with the Latin or Western Church, although they vary in theological emphasis, forms of liturgical worship and popular piety, canonical discipline and terminology. In particular, they recognize the central role of the Bishop of Rome within the College of Bishops and his infallibility when speaking ex cathedra.