Actually, he indeed was part of the leadership before his "treason". He was nominated as commander of the Gallil during the revolt at quite a young age (26 if memory serves). He was supposed to be brilliant and quite a student of the Torah, so his claims are not far from what appears to be the truth. On his mother side, he was a descendent of the Hashmonai house, the leaders of the revolt against the Greek (more successful than the two revolts against the Romans), this revolt against the (Syrian) Greek and the following period of independence is celebrated by the Hannuka holiday.
Zeev