The castle was no less prominent in peace than war, above all, of course, because it was the residence of the great, the centre and the seat of lordship, and this in an age of lordship when a ruling class really ruled. From first to last, as we have seen, the castle was a fortified residence: the residential function was no less fundamental to it than the military; and it was, indeed, this unique duality of residence and fortress that, so to speak, made a castle, and made it different from the fortifications of earlier and later periods. One may say also that it made it feudal, for while it is a matter of historical fact that the castle, the fortified residence of a lord, is the peculiar manifestation of feudal society, it is also entirely appropriate that it should be so. Feudal society, we are told, is society organized for war. It is also most certainly a society dominated by a military and a militant aristocracy, and what more appropriate setting could there be for them than castles? That the seigneurial residence should also be a fortress fits perfectly, and makes manifest, the military ethos of the age, as also do the seals whereon these aristocratic warriors formally represented themselves, or the effigies they had placed upon their tombs, in both cases armed cap à pie. Of course not every lord in the feudal period lived in a castle all the time, and not all lordly residences were fortified, i.e. were castles; but also there is no doubt that the castle became the symbol as well as much of the substance of lordship, and thereby an architectural concept meant to impress. Those castles depicted as rising on the skyline of the Très Riches Heures are real. And meanwhile, also, the castle as the residence of the lord (or his official) became inevitably the centre of local government, as we shall see, and sometimes other things as well, arising from its strength and social eminence.

There is one general feature of this medieval high society which must be noticed before any further discussion of the castle as its characteristic residence. Its members were almost continually on the move.