It wasn't okay for priests to marry, but rather it was/is okay to ordain married men – subtle difference, but important. As one goes further back in time, the

It wasn't okay for priests to marry, but rather it was/is okay to ordain married men – subtle difference, but important. As one goes further back in time, the issue isn't so much about celibacy but about the obligation of sexual continence for those ordained to the ministerial priesthood. In the Christian West, the obligation of perpetual sexual continence (= husband and wife not having sexual intercourse at any time after the husband is ordained) was eventually safeguarded by the obligation of celibacy (= can't be married). In the Christian East, the obligation of perpetual continence was more or less put aside for all but those ordained to the episcopate. Note that Christian monasticism in the East and West entails/ed "evangelical chastity" (cf. the life of Christ and the Apostle Paul; Matthew 19:12, 1 Corinthians 7), so it's a somewhat separate consideration that monks don't marry. Interestingly, in much of the Christian East periodic sexual continence is still an obligation for married priests, i.e. for some period of time prior to their celebration of the eucharistic liturgy. Such periodic sexual continence (or abstinence) of married clergy is sometimes referred to as "levitical continence" while the perpetual variety is referred to as "apostolic". Some of the early Church Fathers maintained that after Pentecost and the birth of the Church, the Apostles of Jesus dedicated themselves in a total way to the spread of the gospel and their ministry, such that they no longer had sexual intercourse with their wives. The lesser form of continence is then seen to be modeled after the obligations of the levitical priesthood of ancient Judaism. A greater share in the apostolic ministry (bishop vs. simple priest) thus entails a greater obligation of continence. To safeguard that obligation, it is the general practice in the Christian East to only ordain to the episcopate men who have already committed themselves to a life of perpetual continence, i.e. monastic clergy.