Nor is it in the sphere of taxation alone that Williams organization of the realm stands on the old English customs. In the military sphere, though his normal army is the feudal force composed of the tenants-in-chief and the knights whom they have enfeoffed, he retains the power to call out the fyrd, the old national levee en masse, without regard to whether its members are freemen or villeins of some lord.
It revised the arming andorganization of the Statute of national militia, the lineal descendent of the old fyrd, cheser.
Again, the fird (fyrd) was composed of mounted warriors during the 9th century, though apparently they fought on foot, and there are indications that such was the case also in the 7th century.
It is first mentioned in the Anglo-Saxon Chronicle under the date 605.The ealdorman, or sheriff, of the shire was probably charged with the duty of calling out and leading the fyrd, which appears always to have retained a local character, as during the time of the Danish invasions we read of the fyrd of Kent, of Somerset and of Devon.
The fyrd was gradually superseded by the gathering of the thegns and their retainers, but it was occasionally called out for defensive purposes even after the Norman Conquest.