From its inception, the apostolic Church spread east and west. In due time the churches in these areas took on the language, traditions and culture in which they found themselves. In the west, the Church grew up in the predominantly Roman Latin culture and became the Roman Catholic Church. In the east, the Church became more and more associated with Greek Byzantium. Each developed its own legitimate and distinctive spirituality, liturgical tradition and internal discipline. For the first thousand years, both allowed married men to be ordained, while monks and religious maintained celibate chastity. Beginning in the 11th century, for a variety of reasons, some spiritual, some practical, the Latin Church embraced the discipline of celibate chastity for all its clergy. The eastern churches, meanwhile, maintain a married diocesan clergy to the present day.
The Eastern Catholic Churches are those churches of eastern heritage who are in full communion with the Holy See. As such, being true to their heritage, they are allowed to maintain the discipline of ordaining married men to the diocesan priesthood, however, a priest cannot marry after ordination. As in the other eastern churches, monks and bishops are always celibate. As my colleague Fr. Ron Roberson, CSP, says, “In the eastern churches, married men can get ordained, but ordained men cannot get married.”