Flag of Mercia

Kingdom of Mercia
Miercna rīce  (Old English) Merciorum regnum  (Latin)
Independent kingdom (527–879) Client state of Wessex (c. 879–918)
527–918
Flag
The Kingdom of Mercia (thick line) and the kingdom's extent during the Mercian Supremacy (green shading)
Capital		Tamworth
Languages		Old English, Latin
Religion		Paganism, Christianity
Government		Absolute monarchy
Monarch
•	527–?	Icel (first)
•	c. 626–655	Penda
•	716–757	Ethelbald
•	757–796	Offa
•	c. 881–911	Ethelred
•	918	Ælfwynn (last)
Legislature		Witenagemot
Historical era		Heptarchy
•	Established	527
•	Disestablished	918
Preceded by Succeeded by Sub-Roman Britain Hwicce Kingdom of Lindsey Kingdom of Northumbria Kingdom of Wessex
Today part of		United Kingdom  ∟ West Midlands  ∟ East Midlands  ∟ East of England  ∟ Greater London  ∟ Yorkshire & the Humber (N. Lincs. and NE Lincs.)  ∟ northern parts of South East England (incl. Berks., Beds., Herts., Oxon. Surrey, and Bucks.)  ∟ North West England (Cheshire, Merseyside, Greater Manchester)  ∟ Wales (Flintshire and Wrexham)

Mercia (Old English: Miercna rīce) was one of the kingdoms of the Anglo-Saxon Heptarchy. The name is a Latinisation of the Old English Mierce or Myrce, meaning "border people" (see March).

The kingdom was centred on the valley of the River Trent and its tributaries, in the region now known as the English Midlands. The kingdom's "capital" was the town of Tamworth, which was the seat of the Mercian Kings from at least around AD 584, when King Creoda built a fortress at the town.

For 300 years (between AD 600 and 900), having annexed or gained submissions from five of the other six kingdoms of the Heptarchy (East Anglia, Essex, Kent, Sussex and Wessex), Mercia dominated England south of the River Humber: this period is known as the Mercian Supremacy. The reign of King Offa, who is best remembered for his Dyke that designated the boundary between Mercia and the Welsh kingdoms, is sometimes known as the "Golden Age of Mercia". Nicholas Brooks noted that "the Mercians stand out as by far the most successful of the various early Anglo-Saxon peoples until the later ninth century", and some historians, such as Sir Frank Stenton, believe the unification of England south of the Humber estuary was achieved during the reign of Offa.

Mercia was originally a pagan kingdom, but King Peada converted to Christianity around 656, and Christianity was firmly established in the kingdom by the late 7th century. The Diocese of Mercia was founded in 656, with the first bishop, Diuma, based at Repton. After only 13 years at Repton, in 669 the fifth bishop, Saint Chad, moved the bishopric to Lichfield, where it has been based ever since. In 691, the Diocese of Mercia became the Diocese of Lichfield. For a brief period between 787 and 799 the diocese was an archbishopric, although it was officially dissolved in 803. The current bishop, Michael Ipgrave, is the 99th since the diocese was established.