An archbishopric in Mercia would also reinforce the kingdom's independence and free it from ecclesiastical dependence on Canterbury in the kingdom of Kent, which Offa had recently brought under Mercian control. Jænberht supported the Kentish king Egbert II, who was not known as a firm supporter of Offa's; an archbishop at Canterbury who was either indifferent or in active opposition to Offa would be an impediment to Offa's ability to establish overlordship of Kent and other areas of England. By elevating another archbishop, Offa would reduce the political power of the archbishops of Canterbury. Elevation of a bishopric to an archbishopric was not unprecedented; in 735 the papacy had elevated another Anglo-Saxon bishopric to an archbishopric, when Ecgbert became the first Archbishop of York.