The military interpretation of castles first began to be questioned in the 1960s when archaeological research began to address the problem of castle origins. As a result of systematic field survey, it was realised that many of the very earliest Norman castles were not of motte and bailey type but were ringworks (an oval enclosure with bank and ditch). In 1966, B. K. Davison pointed out that there seemed to be a lack of mottes in Normandy prior to 1066 and that the motte and bailey may only have developed during the Norman Conquest of England. In 1967, he went further and suggested (before a major series of archaeological excavations at a number of early Norman castles designed to test the point) that ringworks must have been known in pre-Conquest England and implied that if a castle was defined as a ‘fortified residence of a lord’ then, de facto, the idea of private fortification being new to England in 1066 was incorrect. This provoked a fierce backlash from R. Allen Brown who vigorously restated the case for the castle being a Norman import and suggested that Ella Armitage had answered all the major questions over origins a generation earlier. As it transpired, the series of excavations in the late 1970s did not come to any clear-cut conclusions on the issue but an important line of future enquiry had been put on the agenda. (Robert Liddiard, 2010, Historical Insights: Focus on Teaching Medieval Castles p. 9