The Greek-Catholic Churches or Byzantine Catholic Churches, are sui iuris Churches which fall within the "Eastern Catholic Churches" or "Catholic Churches of Eastern rite", which constitute the corpus of churches in communion with the Bishop of Rome and observing, by long tradition, the Byzantine Rite. These bodies of Churches were traditionally called "Greek-Catholic" to highlight the "Greek" origin of the rite as contrasted with the Latin Church of the west. Despite using the word Greek, the vast majority of Byzantine Catholics come from the Slavic Byzantine tradition with Ukrainian Catholics being the largest body.