To strengthen resistance to Irene, Charlemagne reached out to Offa and Cynethryth through letters, even offering his son Charles in marriage to their daughter. In an act of brazen one-upmanship, Offa displayed his arrogance on the world stage by suggesting his son Ecgfrith should also marry Charlemagne’s daughter Bertha. This led to a break in friendly relations between the Holy Roman Empire and Mercia,
