<P> Anglo--Saxon building forms were very much part of this general building tradition . Timber was' the natural building medium of the age': the very Anglo--Saxon word for' building' is' timbe' . Unlike in the Carolingian world, late Anglo--Saxon royal halls continued to be of timber in the manner of Yeavering centuries before, even though the king could clearly have mustered the resources to build in stone . Their preference must have been a conscious choice, perhaps an expression of' deeply--embedded Germanic identity' on the part of the Anglo--Saxon royalty . </P> <P> The major rural buildings were sunken - floor (Grubenhäuser) or post-hole buildings, although Helena Hamerow suggest this distinction is less clear . Even the elite had simple buildings, with a central fire and a hole in the roof to let the smoke escape and the largest of which rarely had more than one floor, and one room . Buildings vary widely in size, most were square or rectangular, though some round houses have been found . Frequently these buildings have sunken floors; a shallow pit over which a plank floor was suspended . The pit may have been used for storage, but more likely was filled with straw for winter insulation . A variation on the sunken floor design is found in towns, where the "basement" may be as deep as 9 feet, suggesting a storage or work area below a suspended floor . Another common design was simple post framing, with heavy posts set directly into the ground, supporting the roof . The space between the posts was filled in with wattle and daub, or occasionally, planks . The floors were generally packed earth, though planks were sometimes used . Roofing materials varied, with thatch being the most common, though turf and even wooden shingles were also used . </P> <P> Stone could be used, and was used, to build churches . Bede makes it clear in both his Ecclesiastical History and his Historiam Abbatum that the masonry construction of churches, including his own at Jarrow, was undertaken morem Romanorum,' in the manner of the Romans,' in explicit contrast to existing traditions of timber construction . Even at Canterbury, Bede believed that St Augustine's first cathedral had been' repaired' or' recovered' (recuperavit) from an existing Roman church, when in fact it had been newly constructed from Roman materials . The belief was "the Christian Church was Roman therefore a masonry church was a Roman building". </P> <P> The building of churches in Anglo - Saxon England essentially began with Augustine of Canterbury in Kent following 597; for this he probably imported workmen from Frankish Gaul . The cathedral and abbey in Canterbury, together with churches in Kent at Minster in Sheppey (c. 664) and Reculver (669), and in Essex at the Chapel of St Peter - on - the - Wall at Bradwell - on - Sea, define the earliest type in southeast England . A simple nave without aisles provided the setting for the main altar; east of this a chancel arch separated off the apse for use by the clergy . Flanking the apse and east end of the nave were side chambers serving as sacristies; further porticus might continue along the nave to provide for burials and other purposes . In Northumbria the early development of Christianity was influenced by the Irish mission, important churches being built in timber . Masonry churches became prominent from the late 7th century with the foundations of Wilfrid at Ripon and Hexham, and of Benedict Biscop at Monkwearmouth - Jarrow . These buildings had long naves and small rectangular chancels; porticus sometimes surrounded the naves . Elaborate crypts are a feature of Wilfrid's buildings . The best preserved early Northumbrian church is Escomb Church . </P>

What were the two main forces that united the anglo-saxons into one nation