Germanic warlords, later named as Hengist and Horsa by Bede, to settle their people on the Isle of Thanet in exchange for their service as mercenaries. According to Bede, Hengist manipulated Vortigern into granting more land and allowing for more settlers to come in, paving the way for the Germanic settlement of Britain. Historians are divided about what followed: some argue that the takeover of southern Great Britain by the Anglo-Saxons was peaceful. The known account from a native Briton who lived in the mid-5th century AD, Gildas, described events as a forced takeover by armed attack: Gildas described how the Saxons were later slaughtered at the battle of Mons Badonicus 44 years before he wrote his history, and their conquest of Britain halted. The eighth-century English historian Bede tells how their advance resumed thereafter. He said this resulted in a swift overrunning of the entirety of South-Eastern Britain, and the foundation of the Anglo-Saxon kingdoms. Four separate Saxon realms emerged: East Saxons: created the Kingdom of Essex. Middle Saxons: created the province of Middlesex South Saxons: led by Aelle, created the Kingdom of Sussex West Saxons: created the Kingdom of Wessex During the period of the reigns from Egbert to Alfred the Great, the kings of Wessex emerged as Bretwalda, unifying the country. They eventually organised it as the kingdom of England in the face of Viking invasions. Later Saxons in Germany The continental Saxons living in what was known as Old Saxony (c. 531–804) appear to have become consolidated by the end of the eighth century. After subjugation by the Emperor Charlemagne, a political entity called the Duchy of Saxony (804-1296) appeared, covering Westphalia, Eastphalia, Angria and Nordalbingia (Holstein, southern part of modern-day Schleswig-Holstein state). The Saxons long resisted becoming Christians and being incorporated into the orbit of the Frankish kingdom. In 776 the Saxons promised to convert to Christianity and vow loyalty to the king, but, during Charlemagne's campaign in Hispania (778), the Saxons advanced to Deutz on the Rhine and plundered along the river. This was an oft-repeated pattern when Charlemagne was distracted by other matters. They were conquered by Charlemagne in a long series of annual campaigns, the Saxon Wars (772804). With defeat came enforced baptism and conversion as well as the union of the Saxons with the rest of the Germanic, Frankish empire. Their sacred tree or pillar, a symbol of Irminsul, was destroyed.