Complex sentence: Around the beginning of the 20th century, the tribe cooperated with the Ikhwan movement who were endorsed by the Al Saud clan of Najd, but at that period tended to side more with the Sharifs of Mecca H. Kindermann-(C.E. Bosworth).
Split into simpler sentences: Around the beginning of the 20th century, the tribe cooperated with the Ikhwan movement who were endorsed by the Al Saud clan of Najd. However, at the time they tended to side more with the Sharifs of Mecca H. Kindermann-(C.E. Bosworth).