Feudalism is a construct, an intellectual model which may or may not reflect the past reality it tries to describe. As modern constructs go it is quite an antique. As a historical model of medieval society it grew out of the work of antiquarian lawyers early in the sixteenth and seventeenth centuries. Frederic Maitland had some telling and ironic things to say about this sort of 'feudalism', ignored because their irony made them seem quirky. He sent up the contemporary debate on the introduction of feudalism by remarking that it was Spelman who brought the feudal system to England. Under the influence of Duby, the key feature of feudalism in medieval society became the transformation it worked on society, and the key phase of that transformation was for him around the year 1000. The only serious argument in favour of talking about feudalism is that it describes a characteristic medieval social order, whose core is its transitional nature.