Mercia: One of the kingdoms of the Anglo-Saxon Heptarchy

It was in the region now known as the English Midlands now East Midlands & West Midlands. Mercia was centered on the valley of the River Trent and its tributaries. Settled by Angles, their name is the root of the name 'England'. Their neighbors included other Angles, Saxons and Jutes all from Germany. Mercia bordered on Northumbria, Wessex, Sussex, Essex and East Anglia. To the west were Britons in Powys and the kingdoms of southern Wales. Its capital was Tamworth, which is today part of Staffordshire.

Archaeological discoveries show the first Anglian settlements were in the Trent river valley. The original kingdom of Mercia had a variety of different kinds of land. Most of it would not have been the first choice of anyone wishing to settle there. Not if better land was available elsewhere. The name 'Mercia' comes from the tribal name Mierce, which means 'boundary folk.' It was probably a name already known in the English midlands and was adopted by the Angles who settled there. The Angles, according to Bede, came from Angulus in northern Germany. They were of the same stock as the East Anglians and the Northumbrians. The invasion of England by the Germanic tribes was relatively quick. By c. 650 England was a large collection of small kingdoms each having a warlord or petty king. Within 200 years of their arrival in England, the late seventh century, emerged the Heptarchy: the seven kingdoms of Anglo-Saxon England. Mercia was the dominant power among the Anglo-Saxons from the middle of the seventh century to the early ninth century. Several Mercian noblewomen played an important role in Mercian affairs. This is in contrast to Wessex where women rarely had an active role in the government. During the seventh and eighth centuries Mercia struggled mainly with Northumbria. By the ninth century Wessex was the dominant power in the region. King Egbert of Wessex (802–839) was the overlord and for the first time passed this position down to his heirs. From this time on until they ceased to exist as a kingdom, Mercia was a vassal kingdom to Wessex. In the last quarter of the ninth century Mercia lost much of its territory in the midlands to Danish settlers.

Christianity was introduced into Mercia in the 650s. The first monks were Irish followed by Northumbrians. By 653 a single bishopric was established and a series of Irish trained bishops followed. In 674 a second diocese was established for eastern Mercia.

Penda (c. 626–655) was a pagan king of Mercia. He was able to put together a confederacy of a number of smaller kingdoms and from that he created Mercia. But in the 630s he was not able to compete with the larger Anglo-Saxon kingdoms that were around his. Northumberland was threatening to expand into the territory of Mercia. Penda found it convenient to ally with Gwynedd, the dominant British kingdom to the west. It was an unusual cooperation between Christians and pagans, but it worked. Together they defeated the Northumbrian king, Edwin, who died at the battle of Hatfield Chase.

Athelred I (675–716) was the third of Penda's sons to be king of Mercia. He ravaged Kent to prevent them from breaking away from his rule. In 679 he was at war with Northumbria. According to Bede, Theodore Archbishop of Canterbury mediated between the two kings to restore peace. He married Ostryth, daughter of the king of Bernicia. He was a Christian king who founded several churches and monasteries. He stepped down as king in 704 and passed the crown to his nephew Cenred. He was abbot of the monastery of Bardsey and appears to have died about 716.

Offa (757–796), was the first of the Anglo-Saxon kings who might rightly be called "king of the English". He was the son of Thingfrith, the brother of Penda. He struggled to gain control of Mercia having come to power just after a civil war. But he proved to be ruthless, bold and creative in bringing Kent, Sussex and Essex under his control. Offa had diplomatic relations with Charlemagne. He was one of the few Anglo-Saxon monarchs to have dealings with continental rulers. Letters and presents were exchanged. But when Offa sought a marriage of his son to one of Charlemagne's daughters, relations were quickly cut off. Frankish ports were closed to British ships. Offa, very involved in church affairs, presided over church councils personally in 786-7. In 787 he convinced the pope to create the position of archbishop of Lichfield in Mercia. He wanted his own archbishop who was closer at hand than the Archbishop of Canterbury. He reorganized the defenses of his kingdom. One of these defenses, Offa's Dyke was a massive earthworks between Mercia and the Welsh kingdoms to the west. Offa died in 796. His son, Ecgfrith, lasted only 141 days as king. Mercia was never again as powerful as it was during Offa's reign.

A new Mercian king, Raedwulf, was killed by Viking raiders in 844. In 855 Viking bands were recorded as being in Mercia near Wrekin. But the year 865 saw a major change in activity by the Scandinavian invaders. This was a much larger military force than had been seen before. The arrival of the Great Heathen Army in East Anglia. For a time the Danes (Vikings) were more interested in Northumbria. They gained control of York and moved south into Mercia then camped for the winter in Nottingham. In the spring of 868 a combined Mercian and West Saxon army came against the Vikings, but there was no battle. The Mercian king Burghred made a peace treaty with the invaders, who then moved north to York. In 873 Burghred was forced out of Mercia by the Vikings who then set their own choice of King, Ceowulf. In 874 the heathen army split with Halfdan, one of the leaders taking his band north. In 878 the Vikings in Mercia were attacked and defeated by King Alfred of Wessex. They converted to Christianity and settled on the land in East Anglia.

The ninth century saw the decline of Mercia as a kingdom. In 873-74 Mercia was conquered by the heathen army. In the 880s Wessex formed a marriage alliance with Mercia. Alfred's daughter, Aethelflaed , married Aethelred (II), of Mercia. When Aethelred died, in 912, Edward the Elder appointed Aethelflaed (his sister) 'Lady of the Mercians.' When Aethelflaed died in 918, the Mercian nobles now thought themselves free of Wessex rule. Edward stepped in and appointed Aethelflaed's daughter, Aelfwynn, to rule Mercia as his representative. But in 919 Edward brought her back to Wessex. After that Mercia was considered just another shire under his rule. A series of ealdormen (similar to a count in Europe) followed. Under Canute in 1017, Mercia became one of the four divisions of England.