And the requirement of CONTINENCE applies to married clerics as well as the unmarried.
Was this always Church teaching? Is there support for this in Catholic teaching before the Church decided on a predominantly unmarried clergy?
Also, are we to assume that those clergy that are/were married, are continent with their wives?
Dr. Edward Peters answers these questions.
The tradition goes back to the apostles.
The scenario that is believed by many--that most priests were married for many centuries, and celibacy was "imposed" by fiat--is a myth.
You are no doubt familiar with the way Protestant controversialists will quote a council or Pope reaffirming a dogma (e.g., transubstantiation) in the 12th, 13th, 14th, 15th, or even a later century, and confidently announce that the Church "invented" the dogma at that late date. The same error has been made time and again regarding clerical celibacy.