Beorhtwulf (Old English: [ˈbeorˠxtwuɫf], meaning "bright wolf"; also spelled Berhtwulf; died 852) was King of Mercia, a kingdom of Anglo-Saxon England, from 839 or 840 to 852.

Charters from Beorthwulf's reign show a strained relationship with the church, as Beorhtwulf seized land and subsequently returned it.

[1] Mercian influence in the south-eastern kingdoms of Kent, East Anglia, and Essex continued into the early 820s under Coenwulf of Mercia.

[2] However, Coenwulf's death in 821 marked the beginning of a period in which Mercia suffered from dynastic conflicts and military defeats that redrew the political map of England.

The C group, which included the brothers Coenwulf, Cuthred of Kent, and Ceolwulf I, was dominant in the period following the deaths of Offa of Mercia and his son Ecgfrith in 796.

Beorhtwulf, who succeeded to the throne that year, is likely to have come from the B group, which may also have included the ill-fated Beornred who "held [power] a little while and unhappily" after the murder of King Æthelbald in 757.

Such a witness list can be seen on the Ismere Diploma, for example, where Æthelric, son of king Oshere of the Hwicce, is described as a "subregulus", or subking, of Æthelbald of Mercia.

Historian D. P. Kirby suggests that Wiglaf's death occurred in 839, basing this date on the known chronology of the reigns of Beorhtwulf and Burgred, the next two Mercian kings.

An alternative explanation for Beorhtwulf's revival of the coinage is that it was part of a plan for economic regeneration in the face of the Viking attacks.

The Viking threat may also account for the evident cooperation in matters of currency between Mercia and Wessex which began in Beorhtwulf's reign and lasted until the end of the independent Mercian kingdom on the death of King Ceolwulf II in the years around 880.

In the battle of Catill[15] or Cyfeiliog,[16] he killed King Merfyn Frych of Gwynedd[16] and later sources imply (see below) that he was able to subjugate the northern Welsh after this.

However, the Anglo-Saxon Chronicle records Viking raids in 841 against the south and east coasts of Britain, including the Mercian province of Lindsey, centred on modern Lincoln.

In 844 Ceolred, the bishop of Leicester, granted Beorhtwulf an estate at Pangbourne, in Berkshire, so the area was still in Mercian hands at that date.

The problem had been mentioned over a century before by Bede, who in a letter to Egbert, the Archbishop of York, had complained of "a complete lack of places where the sons of nobles and of veteran thegns can receive an estate".

A charter of the late 840s released the monastery of Breedon on the Hill from the requirement to supply food and lodging to Beorhtwulf's servants and messengers, including "the royal hawks, huntsmen, horses, and their attendants".

A second Viking force of 350 ships is reported by the Anglo-Saxon Chronicle to have stormed Canterbury and London, and to have "put to flight Beorhtwulf, king of Mercia, with his army".

[23] The Vikings were defeated by Æthelwulf and his sons, Æthelstan and Æthelbald, but the economic impact appears to have been significant, as Mercian coinage in London was very limited after 851.

[34] The story of Beorhtwulf's other known son, Beorhtfrith, is told in the Passio sancti Wigstani, which may include material from a late 9th-century source, with some corroboration in the chronicle of John of Worcester.

Beorhtfrith wished to marry the royal heiress Ælfflæd, King Ceolwulf's daughter, widow of Wiglaf's son Wigmund and mother of Wigstan.