When the Romans came to the island Albion, they first conquered Brittania (Britania), the land of the Brittones. They made Cirencester the capital of this province lying south of the rivers Mersey and Humber. Next, they advanced northwards into Brigantia, the land of the Brigentes, and made York its capital. They rename the provinces Brigantia Prima and Britania Secunda, respectively. (The Romans named these Islands as Britain,Britania land of the Brittones) note ;(The Britons were the largest of many other groups)
In the fifth century A.D., the legions were withdrawn to the continent. Picts attacked from the North Pictavia, the Irish ( Scots ) ravaged the provinces from the West, Angles ( Engle ) and Frisians settled in the North East, Jutes from the mouth of the Rhine settled in the South and the South East and Saxons settled in the South and South West entering along the great rivers of the South the Thames and the Severn
Britons from the South West escaped the marauding Scots ( Irish ) by transfering to across the channel where they created a New Britain ( rather like the English in the 17th century went to America and created a New England ) The Engles ( Angles ) moved westwards from the Humber to the region of the Mersey. A new Kingdom became established in what is now Staffordshire and Derbyshire, next to the border between Britannia Prima and Britania Secunda, which gave its name to Newcastle-under-lyme ( Latin Limes) . It was” Mercia ” which adopted Tamworth as its Capital. In the meantime, the Saxons and Jutes had occupied the South and the Southern Midlands, and the Angles, north of the Humber had taken over Britannia Secunda with its capital at York and became Northumberland.
Mercia began a aggresive expansion charting Saxon territory of Herefordshire, Gloucestershire, Worcestershire, and Oxfordshire. They expanded Eastwards into Anglian Southumberia. They swung southwards capturing Essex, Kent, Sussex, Berkshire, and Hampshire and squeezing ( Wessex) West Saxon. Having defeated the Britons of Devon, West Saxon ( Wessex) turned to recovering lands from the Mercian Angles. In AD 824 , Surrey, Sussex, Kent, and Essex, ( Greater Wessex ) were added to Wessex, Oxfordshire and then Berkshire were recovered from Mercia.
During the Viking age, Northumbria succumed to the invaders. Mercia was devided between the Saxons and the Danes under a treaty between King Alfred and the Viking Leader Guthorum. Anglian Mercia along with Essex passed into Danish Hands, Saxon Mercia Gloucestershire, Herefordshire, and Worcestershire were reunited with West Saxons (Wessex). In 1066 King Harold the second Godwineson having conquered Wales, found England under attack from a Flemish army led by his brother Tostig in coalition with the Norwegian King Harold Hardrada. Tostig and Harold Hardrada inflicted a heavy defeat on the Angles at the Battle of Fulford. Harold Godwineson with an army of improvised Saxon Warriors raced Northwards and gained a Great Victory at Stamford Bridge. A Victory gained with the slaying of his brother Tostig and the Norwegian King Harold Hardrada, Morcar was restored to the Earldom of Northumbia.
But for the battle of Fulford, Mercia and Northumberland might have stood along side of West Saxon Harold Godwineson, with a different outcome at Hastings. In the beginning, William was content to replace Harold as King of England and Earl of (Wessex) West Saxon and East Anglia. He allowed Morcar and Edwin to remain Earls of Northumberland and Mercia respectively. Even after the brothers had been persuaded by Hereward the Wake to rebel, William forgave them and allowed them to continue to rule their Earldoms. It was only after a second rebellion that William moved against the brothers.
{Note} New Britain became Bretagne (Brittany) leading to the Island of Britain becoming Grand Bretagne ( Great Britain) i.e Big Britain.
Hrothbeorht Sax of Wesseaxe (West Saxons)