most common, though turf and even wooden shingles were also used. The most archaeologically striking example of a royal palace is found at Yeavering (Northumbria). Excavated by Hope-Taylor, the 1977 site report illustrates a complex set of wooden halls, axially aligned. However, John Blair has made clear that, from c. 600 to c. 900, elite settlements are archaeologically invisible. From the mid-10th century onwards, a unique architectural form emerges at high-status thegnly sites - the Long Range. Comprising a combined hall and chambers, these are understood to represent a deliberate set of performative symbols of power and status put in play by the newly powerful thegnly class. During the 9th and 10th centuries, fortifications (burhs) were constructed around towns to defend against Viking attacks. Almost no secular work remains above ground, although the Anglian Tower in York has been controversially dated to the 7th century. Recent evidence opens up the possibility that St George's Tower, Oxford, may be a surviving part of the defences surrounding the Anglo-Saxon burh of Oxford. There is a reconstruction of an Anglo-Saxon settlement at West Stow in Suffolk, and contemporary illustrations of both secular and religious buildings are sometimes found in illuminated manuscripts. Church architecture: historical context The fall of Roman Britain at the beginning of the fifth century, according to Bede, allowed an influx of invaders from northern Germany including the Angles and Saxons. The Angles and the Saxons had their own religion, but Christianity was on its way. St Patrick, a Romano-British man, converted Ireland to Christianity, from where much of Western Scotland was converted and much of Northumbria was reconverted. Links were also established between the Christian communities in Ireland and those in Wales and the West country at sites such as St Piran's Oratory which represents some of the earliest Christian architecture extant on the British mainland. The architecture though was initially influenced by Coptic monasticism. Examples of this can be seen today in the form of rectangular dry-stone corbelled structures such as at Gallarus Oratory, Dingle and Illauntannig, Ireland. Christianity and Irish influence came to England through missionaries. In 635, a centre of Celtic Christianity was established at Lindisfarne, Northumbria, where St Aidan founded a monastery. In 597, the mission of Augustine from Rome came to England to convert the southern Anglo-Saxons, and founded the first cathedral and a Benedictine monastery at Canterbury. These churches consisted of a nave with