roads. Formation of Surrey During the 5th and 6th centuries Surrey was conquered and settled by Saxons. The names of possible tribes inhabiting the area have been conjectured on the basis of place names. These include the (around Godalming) and (between Woking and Wokingham in Berkshire). It has also been speculated that the entries for the and peoples in the Tribal Hidage may refer to two groups living in the vicinity of Surrey. Together their lands were assessed at a total of 7,000 hides, equal to the assessment for Sussex or Essex. Surrey may have formed part of a larger Middle Saxon kingdom or confederacy, also including areas north of the Thames. The name Surrey is derived from (or ), meaning "southern region", and this may originate in its status as the southern portion of the Middle Saxon territory. If it ever existed, the Middle Saxon kingdom had disappeared by the 7th century, and Surrey became a frontier area disputed between the kingdoms of Kent, Essex, Sussex, Wessex and Mercia, until its permanent absorption by Wessex in 825. Despite this fluctuating situation it retained its identity as an enduring territorial unit. During the 7th century Surrey became Christian and initially formed part of the East Saxon diocese of London, indicating that it was under East Saxon rule at that time, but was later transferred to the West Saxon diocese of Winchester. Its most important religious institution throughout the Anglo-Saxon period and beyond was Chertsey Abbey, founded in 666. At this point Surrey was evidently under Kentish domination, as the abbey was founded under the patronage of King Ecgberht of Kent. However, a few years later at least part of it was subject to Mercia, since in 673–675 further lands were given to Chertsey Abbey by Frithuwald, a local sub-king () ruling under the sovereignty of Wulfhere of Mercia. A decade later Surrey passed into the hands of King Caedwalla of Wessex, who also conquered Kent and Sussex, and founded a monastery at Farnham in 686. The region remained under the control of Caedwalla's successor Ine in the early 8th century. Its political history for most of the 8th century is unclear, although West Saxon control may have broken down around 722, but by 784–785 it had passed into the hands of King Offa of Mercia. Mercian rule continued until 825, when following his victory over the Mercians at the Battle