At the request of RabbiO, I have a couple of general questions I am hoping can be clarified. During the late Temple period, just prior to the Roman destruction, as I understand; in Israel was the tribe of Judah, half of the tribe of Levi (the other half having gone into exile with the other tribes), and the remnant of the tribe of Benjamin (decimated previously in a family quarrel, because of which the remainder came under the safekeeping of Judah). Any of this may be clarified if I am not spot on, but I think I'm pretty close. I have a nagging feeling I'm forgetting somebody, but it isn't coming to mind at this moment. Now, the priesthood since Aaron (the <half?> brother of Moses) was hereditary, and this is why the tribe of Levi was not awarded any land or "possessions," G-d was to be their possession. Specifically as I understand, the family Cohen, also known as Kohen, is the direct line of the Levitical Temple Priests. So my question, were those of the tribes of Judah or Benjamin (or any other tribe I'm forgetting) allowed to participate in religious instruction in some capacity? Were Rabbis limited to the tribe of Levi? or could a person born of the tribe of Judah or Benjamin also serve as a Rabbi or some other religious or Temple capacity? I also have to account for the original destruction of the Temple (Nebuchadnezzar?) during the Chaldean captivity, and the reconstruction under Ezra and Nehemiah, during which time I have heard possibility of some alteration of the Temple Priesthood structure, but that was not clarified for me (and understandably the information isn't readily available). So any help clarifying this would also be appreciated. Thanks in advance.