Complex sentence: In the late medieval period, the Clan rebuilt the power base that had been lost by attrition of its senior lines by adoption of families with powerful knights, leading provincial nobility, and several Princes.
Split into simpler sentences: In the late medieval period, the Clan set out rebuilding the power base that had been weakened through attrition of its senior lines. The clan adopted families of powerful knights, leading provincial nobility, and several Princes.