Note of course that the concept of Rabbinical Judaism dates from really after the destruction of the second template in 70 AD, and more specifically to 136 AD with the vast Jewish revolt (many non-Jews etc. were killed in cyprus etc. and the roman reprisal was harsh, banning jews outright from Jerusalem)
Note also that Pontifex Maximus translates as head priest so can be construed as you say Head rabbi. Also, pontifex maximus technically is not a title of the Pope
Also, Vicar derives from Latin Vicarius signifying deputy as in deputy to Christ
Finally "holding dominion over an Empire" -- what are you referring to?
Uuh, that would be the Empire established by Constantine as well as for centuries of rule by the Holy Roman Empire whose allegiance was demanded NOT of and for Jesus Christ, but of and for the Pope/Emperor.
Btw, technical semantics aside, history notes that the "Vicar of Christ" has been anything but in most cases.