David Hume’s's The History of England (1778) tells the story of the Danish conquest of England. (vol. 1, chapter 2 “The Anglo-Saxons”). After a series of wars, the Danes drove King Alfred off the throne, forcing him to flee incognito, disguised as a peasant. Alfred then
retired into the center of a bog, formed by the stagnating waters of the Thone and Parret, in Somersetshire. He here found two acres of firm ground; and building a habitation on them, rendered himself secure by its fortifications, and still more by the unknown and inaccessible roads which led to it, and by the forests and morasses, with which it was every way environed. This place he called Aethelingay, or the Isle of Nobles;t and it now bears the name of Athelney. He thence made frequent and unexpected sallies upon the Danes, who often felt the vigour of his arm, but knew not from what quarter the blow came. He subsisted himself and his followers by the plunder which he acquired; he procured them consolation by revenge; and from small successes, he opened their minds to hope, that, notwithstanding his present low condition, more important victories might at length attend his valour.
In fact, Alfred did emerge later, after having scouted the Danes by going into their camp disguised as a harper. He did eventually drive out many of the Danes, and subdue the rest. He then set about creating better conditions for security from invasion, and from the tyranny which the Danes had once imposed:
The king, after rebuilding the ruined cities, particularly London,e which had been destroyed by the Danes in the reign of Ethelwolf, established a regular militia for the defence of the kingdom. He ordained that all his people should be armed and registered; he assigned them a regular rotation of duty; he distributed part into the castles and fortresses, which he built at proper places;f he required another part to take the field on any alarm, and to assemble at stated places of rendezvous; and he left a sufficient number at home, who were employed in the cultivation of the land, and who afterwards took their turn in military service.g The whole kingdom was like one great garrison; and the Danes could no sooner appear in one place, than a sufficient number was assembled to oppose them, without leaving the other quarters defenceless or disarmed.h
Hume’s footnotes here are:
[g]Ypod. Neustria, p. 414. (Ypodigma Neustriae: A Thoma Walsingham, quondam monacho monasterii S. Albani, conscriptum.)
[h]Chron. Sax. p. 64. (Anglo-Saxon Chronicle).
The Supreme Court’s 1939 decision in United States v. Miller noted Alfred the Great’s creation of a militia for England: “Blackstone’s Commentaries, Vol. 2, Ch. 13, p. 409 points out ‘that king Alfred first settled a national militia in this kingdom,’ and traces the subsequent development and use of such forces.”