When did the title Rav appear in history? and who was the first to be called Rav or Rebbe?
ב"ה Shalom This is a very ancient question and a discussion is brought about it by the 11th century Torah scholar from Italy, R. Natan the son of Yechiel from Rome in his book, the "Aruch" under the entry of Abbaye. אביי There he states that this question was already raised in the Geonic period and was brought before Rav Sherira Gaon. To summarize was he says is that the title "Rabban" came about in the Rabban Gamliel Hazaken (the first Rabban Gamliel) who was appointed as Nassi. He is then followed by Rabban Shimon ben Gamliel , his son and then Rabban Yochanan ben Zakkai. Historically, this means that the title began sometime before the destruction of the second Bet Hamikdash. This is clearly evident also from the Mishna in Pirkei Avot , chapter, where Moshe Rabbenu is mentioned, though without the title Rabbenu, only with his name Moshe. We have Shimon Hatzaddik mentioned, Antignus, Hillel and Shammai all with no title. Then towards the end of the chapter Rabban Gamliel is mentioned. The fact that the earlier greater Rabbis are mentioned without a title doesn't diminish the greatness. Just the opposite, R. Natan of Rome says that greater than the title Rabban is the scholar being called by his own name. Also explained there is that the Rabbis of Eretz Yisrael who were especially ordained to deal with monetary fines "Kenasot" were called Rebbe while the scholars ordained in Bavel were called Rav. All the best