Studies by some Catholic scholars, such as the Ukrainian Roman Cholij and Christian Cochini, have argued for the theory that, in early Christian practice, married men who became priests—they were often older men, "elders"—were expected to live in complete continence, refraining permanently from sexual relations with their wives. When at a later stage it was clear that not all did refrain, the Western Church limited ordination to unmarried men and required a commitment to lifelong celibacy, while the Eastern Churches relaxed the rule, so that Eastern Orthodox and Eastern Catholic Churches now require their married clergy to abstain from sexual relations only for a limited period before celebrating the Eucharist. The Church in Persia, which in the fifth century became separated from the Church described as Orthodox or Catholic, decided at the end of that century to abolish the rule of continence and allow priests to marry, but recognized that it was abrogating an ancient tradition. The Ethiopian Orthodox Tewahedo Church, whose separation, along with the Coptic Orthodox Church of Alexandria, came slightly later, allows deacons (who are ordained when they are boys) to marry after ordination, but not priests: any future priests who wish to marry must do so before becoming priests. The Armenian Apostolic Church, which also belongs to Oriental Orthodoxy, while technically prohibiting, like the Eastern Orthodox Church, marriage after ordination to the sub-diaconate, has generally let this rule fall into disuse and allows deacons to marry up to the point of their priestly ordination, thus continuing to maintain the traditional exclusion of marriage by those who are priests. This theory would explain why all the ancient Christian Churches of both East and West, with the one exception mentioned, exclude marriage after priestly ordination, and why all reserve the episcopate (seen as a fuller form of priesthood than the presbyterate) for the celibate.