Ecgfrith ( 796) was the King of Mercia from July to December 796. He was the son of Offa, the King of Mercia, and Cynethryth. In 787 he was crowned King of Mercia while his father still ruled. This is the first known consecration of an English king. No doubt it was Offs's imitation of the consecration of Charlemagne's sons by the pope in 781. It was a practical way to recognize Ecgfrith as heir to the Mercian kingdom. Offa continued to rule and maintained all the power himself. 