LightSpectra
me autem minui
Baal brings up a really interesting point about mistresses. Was it not always that the Pope was a priest, or that they didn't take vows of celibacy? Or that they simply ignored such rules? Disregarding that St. Pete was numero uno and a Jew (maybe a Rabbi himself, does anyone know the answer to this?) was the Papacy something that evolved into/from a priest's job?
St. Peter had a wife. One of the miracles given by Christ was when he healed St. Peter's sick wife. The concept of clerical celibacy was introduced in the Middle Ages as part of the reforms of Pope St. Gregory VII, though it didn't become an official practice until a bit after that; and it still wasn't even until the Counter-Reformation that it was ably and consistently enforced.
As for the term "Rabbi," it's about as complicated as the term "bishop" due to its many meanings. It roughly translates to "teacher," which is why you hear Jesus being called a rabbi in the Bible. Though the office of a Rabbi as specifically being a Jewish overseer of sorts didn't develop until later.
Popes often disregarded the celibacy rule - not surprising really, given how many other rules they disregarded. I have no idea if the early Popes had such a rule though.
A handful of them did in one particular era when the Papal States were de facto ruled by a couple families that had no respect for the Church. Though the issue isn't so much clerical celibacy as it is fornicating with mistresses.