The Northumbrian king, Æthelred, had been assassinated…
807 CE
The Northumbrian king, Æthelred, had been assassinated in April 796, and less than a month later his successor, Osbald, had been deposed in favor of Eardwulf.
Eardwulf had had Alhmund killed in 800; Alhmund was the son of King Alhred of Northumbria, who had reigned from 765 to 774.
Alhmund's death was regarded as a martyrdom, and his cult subsequently develops at Derby, in Mercian territory, perhaps implying Mercian involvement in Northumbrian politics at the time.
Coenwulf had given hospitality to Eardwulf's enemies, who had been exiled from Northumbria, and consequently Eardwulf in 801 had invaded Mercia.
The invasion was inconclusive, however, and peace had been arranged on equal terms.
Coenwulf may also have been behind the coup in 806 that leads to Eardwulf losing his throne.
Like many of his predecessors, Eardwulf took to exile when he was deposed.
Unlike kings with ties to Lindisfarne, who appear to have chosen exile among the Picts, Eardwulf is linked to Ripon and chooses a southerly exile.
A surviving letter of Leo III to Charlemagne confirms that Eardwulf visited Rome and stayed at Charlemagne's court.