The efficient military might of the Ayyubids meant that they were not seriously threatened by local regimes during 55 years in power. The only disturbing element was the Zaydi imam who was active for part of the period. After 1217 the imamate was split, however.
The Ayyubids' military dominance allowed them to rule for 55 years without significant challenges from local rulers. The only exception was the Zaydi imam who exerted influence during a portion of this period. After 1217, the imamate was divided into two parts.