Not the least brilliant passage in _Domesday Book and Beyond_ was a novel theory as to the origin and early history of the English Borough. The question of municipal origins had produced a library of controversial literature upon the Continent. One writer developed the town from the feudal domain, another from the "immunity," a third from the guild, a fourth from the market, a fifth from the free village, and there were combinations and permutations of these and other factors. Maitland was impressed by the arguments of Dr Keutgen of Jena, who found the origin and criterion of the German borough in its fortification. The idea transplanted into Maitland's mind became surprisingly fruitful. Scattered fragments of evidence seemed to confirm the surmise that in the English Midlands at least the county town was the county fortress, owing its origin to military necessity and supported by a variety of artificial arrangements. There was the evidence of language, for borough originally means a fortified house; the evidence of the map, for in many counties of England the county town is somewhere near the centre; the evidence of warlike stress, for the Danes were foemen even more terrible than those wild Hungarians against whom Henry the Fowler built his Saxon "burhs"; the evidence of Domesday Book, showing contrivances at once careful and varied for maintaining town walls and town garrisons; and here and there a gleam of light from older documents, from the Burghal Hidage of the tenth century, or from a charter of King Alfred. The argument, which was expounded with beautiful clearness and ingenuity, led on to the conclusion that the town court was the product of "tenural heterogeneity," for the garrison men holding of different lords would need a special court to decide their controversies. There was thus a greater degree of governmental artifice in the process than had hitherto been suspected. The borough was not merely a very prosperous village; it was a unit in a scheme of national defence; a fortified town maintained by a district for military purposes with "mural houses" and "knight guilds" and a miscellaneous garrison contributed by shire thegns. By degrees trade, commerce, agriculture, the interests of the market and the town fields would overpower the military characteristics of the county stronghold. But the scheme should not be pressed too far; "no general theory will tell the story of every or any particular town."