Our understanding of early Judaism and its relationship to Christianity has been significantly advanced by Alan Segal’s formative work on the two powers heresy. This work demonstrated that belief in two heavenly powers was considered an intolerable heresy by the rabbis and that Christians were among those indicted. Furthermore, Segal argued that the two powers debate could be traced back to the first century, as evidenced by certain christological passages of the NT4 and by Philo's writings.