Complex sentence: The worship of female powers is likely to have played a greater role than the medieval sources indicate, because those texts were written by men and pay less attention to religious practices in the female sphere than those connected to the male.
Split into simpler sentences: The worship of female powers is likely to have played a greater role than what is told by medieval sources. This is due to those texts being written by men and that religious practices in the female sphere were thus to a lesser degree reported than those connected to the male.