in that it asserted Ecgfrith's royal status while his father was still alive. Offa would have been aware that Charlemagne's sons, Pippin and Louis, had been consecrated as kings by Pope Adrian, and probably wished to emulate the impressive dignity of the Frankish court. Other precedents did exist: Æthelred of Mercia is said to have nominated his son Coenred as king during his lifetime, and Offa may have known of Byzantine examples of royal consecration. Despite the creation of the new archdiocese, Jænberht retained his position as the senior cleric in the land, with Hygeberht conceding his precedence. When Jænberht died in 792, he was replaced by Æthelheard, who was consecrated by Hygeberht, now senior in his turn. Subsequently, Æthelheard appears as a witness on charters and presides at synods without Hygeberht, so it appears that Offa continued to respect Canterbury's authority. A letter from Pope Adrian to Charlemagne survives which makes reference to Offa, but the date is uncertain; it may be as early as 784 or as late as 791. In it Adrian recounts a rumour that had reached him: Offa had reportedly proposed to Charlemagne that Adrian should be deposed, and replaced by a Frankish pope. Adrian disclaims all belief in the rumour, but it is clear it had been a concern to him. The enemies of Offa and Charlemagne, described by Adrian as the source of the rumour, are not named. It is unclear whether this letter is related to the legatine mission of 786; if it predates it, then the mission might have been partly one of reconciliation, but the letter might well have been written after the mission. Offa was a generous patron of the church, founding several churches and monasteries, often dedicated to St Peter. Among these was St Albans Abbey, which he probably founded in the early 790s. He also promised a yearly gift of 365 mancuses to Rome; a mancus was a term of account equivalent to thirty silver pennies, derived from Abbasid gold coins that were circulating in Francia at the time.<ref name=Stenton_223>Stenton, Anglo-Saxon England, p. 223.</ref> Control of religious houses was one way in which a ruler of the day could provide for his family, and to this end Offa ensured (by acquiring papal privileges) that many of them would remain the property of his wife or children after his death. This policy of treating religious houses as worldly