Offa of Mercia

Offa (c. 730 – 29 July 796 AD) was King of Mercia, a kingdom of Anglo-Saxon England, from 757 until his death in 796. The son of Thingfrith and a descendant of Eowa, Offa came to the throne after a period of civil war following the assassination of Æthelbald. Offa defeated the other claimant, Beornred. In the early years of Offa's reign, it is likely that he consolidated his control of Midland peoples such as the Hwicce and the Magonsæte. Taking advantage of instability in the kingdom of Kent to establish himself as overlord, Offa also controlled Sussex by 771, though his authority did not remain unchallenged in either territory. In the 780s he extended Mercian Supremacy over most of southern England, allying with Beorhtric of Wessex, who married Offa's daughter Eadburh, and regained complete control of the southeast. He also became the overlord of East Anglia and had King Æthelberht II of East Anglia beheaded in 794, perhaps for rebelling against him.

Offa was a Christian king who came into conflict with the Church, particularly with Jænberht, the Archbishop of Canterbury. Offa persuaded Pope Adrian I to divide the archdiocese of Canterbury in two, creating a new archdiocese of Lichfield. This reduction in the power of Canterbury may have been motivated by Offa's desire to have an archbishop consecrate his son Ecgfrith as king, since it is possible Jænberht refused to perform the ceremony, which took place in 787. Offa had a dispute with the Bishop of Worcester, which was settled at the Council of Brentford in 781.

Many surviving coins from Offa's reign carry elegant depictions of him, and the artistic quality of these images exceeds that of the contemporary Frankish coinage. Some of his coins carry images of his wife, Cynethryth—the only Anglo-Saxon queen ever depicted on a coin. Only three gold coins of Offa's have survived: one is a copy of an Abbasid dinar of 774 and carries Arabic text on one side, with "Offa Rex" on the other. The gold coins are of uncertain use but may have been struck to be used as alms or for gifts to Rome.

Many historians regard Offa as the most powerful Anglo-Saxon king before Alfred the Great. His dominance never extended to Northumbria, though he gave his daughter Ælfflæd in marriage to the Northumbrian king Æthelred I in 792. Historians once saw his reign as part of a process leading to a unified England, but this is no longer the majority view: in the words of historian Simon Keynes, "Offa was driven by a lust for power, not a vision of English unity; and what he left was a reputation, not a legacy." His son Ecgfrith succeeded him after his death, but reigned for less than five months before Coenwulf of Mercia became king.

In the first half of the 8th century, the dominant Anglo-Saxon ruler was King Æthelbald of Mercia, who by 731 had become the overlord of all the provinces south of the River Humber. Æthelbald was one of a number of strong Mercian kings who ruled from the mid-7th century to the early 9th, and it was not until the reign of Egbert of Wessex in the 9th century that Mercian power began to wane.

The power and prestige that Offa attained made him one of the most significant rulers in early medieval Britain, though no contemporary biography of him survives. A key source for the period is the Anglo-Saxon Chronicle, a collection of annals in Old English narrating the history of the Anglo-Saxons. The Chronicle was a West Saxon production, however, and is sometimes thought to be biased in favour of Wessex; hence it may not accurately convey the extent of power achieved by Offa, a Mercian. That power can be seen at work in charters dating from Offa's reign. Charters were documents which granted land to followers or to churchmen and were witnessed by the kings who had the authority to grant the land. A charter might record the names of both a subject king and his overlord on the witness list appended to the grant. 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's. The eighth-century monk and chronicler the Venerable Bede wrote a history of the English church called Historia Ecclesiastica Gentis Anglorum; the history only covers events up to 731, but as one of the major sources for Anglo-Saxon history it provides important background information for Offa's reign.

Offa's Dyke, most of which was probably built in his reign, is a testimony to the extensive resources Offa had at his command and his ability to organise them. Other surviving sources include a problematic document known as the Tribal Hidage, which may provide further evidence of Offa's scope as a ruler, though its attribution to his reign is disputed. A significant corpus of letters dates from the period, especially from Alcuin, an English deacon and scholar who spent over a decade at Charlemagne's court as one of his chief advisors, and corresponded with kings, nobles and ecclesiastics throughout England. These letters in particular reveal Offa's relations with the continent, as does his coinage, which was based on Carolingian examples.

Offa's ancestry is given in the Anglian collection, a set of genealogies that include lines of descent for four Mercian kings. All four lines descend from Pybba, who ruled Mercia early in the 7th century. Offa's line descends through Pybba's son Eowa and then through three more generations: Osmod, Eanwulf and Offa's father, Thingfrith. Æthelbald, who ruled Mercia for most of the forty years before Offa, was also descended from Eowa according to the genealogies: Offa's grandfather, Eanwulf, was Æthelbald's first cousin. Æthelbald granted land to Eanwulf in the territory of the Hwicce, and it is possible that Offa and Æthelbald were from the same branch of the family. In one charter Offa refers to Æthelbald as his kinsman, and Headbert, Æthelbald's brother, continued to witness charters after Offa rose to power.