Ii. chronology number the order of each event. changes in medieval europe the frankish empire becomes a strong power in europe, but people are still threatened by invaders like the vikings and the magyars. there was significant growth in towns. increased agricultural production led to increased trade and commerce. feudalism came to an end. feudalism develops, and its social order offers people protection. barbarian kingdoms fought for power in europe after the fall of rome. the crusades christian soldiers gain control of jerusalem. the byzantine empire calls on pope urban for against the seljuk turks. muslim soldiers take back most of the holy land from christians. the seljuk turks conquer parts of the byzantine empire, coming within 100 miles of constantinople. pope urban calls for a crusade.