Whatever may have been the early history of Londinium after the Romans left it, the fact remains that the limits and bounds of the actual city continued for many centuries afterwards. It is known that Alfred the Great caused the walls to be repaired; but the precise significance of this is not great, because he may have been merely carrying out a long-needed work, and from the very solid character of the Roman wall (judging from the fragments that remain) it seems scarcely conceivable that his operations extended lower than the battlements of the wall, unless indeed they comprised the freeing of the ditch and berme from vegetation, obstructions, or other kinds of weakness. What the houses of London were like when Alfred repaired the wall is not known. Probably they were constructed of timber and were humble in size and ornamentation. It is doubtful if anything of the nature of a house built of masonry was constructed in London before the twelfth century. No trace of such a structure is known to remain, but there is reason to think that such buildings existed within the boundary of the city of London. What the twelfth century house was like is well seen in the charming example standing close by the castle mound at Christchurch, Hampshire. In plan it is an oblong of modest proportions. The lowest storey was low-pitched and lighted by mere slits for windows. The first floor contained the principal rooms, which were lighted by double-light, round-headed windows. The whole idea was to obtain a residence which would be sufficiently strong to keep out robbers and resist fire. Many of the architectural peculiarities of the old city of London which the Great Fire swept away may be attributed to the fact that the city was bounded by a wall too small for the requirements of the population. The problem of adequately housing the people of London must have become acute at a comparatively early period, certainly before the time of the dreadful pestilence commonly known as the Black Death (1348-1349). The value of space within the city, and the jealousy with which the rights of property were guarded, are shown by the narrowness and crookedness of the streets and lanes. Every available inch was occupied by houses and shops, and as little as possible was devoted to thoroughfares. The sinuosity of the public ways indicates in another way the great value of land, because it obviously arose from the existence of individual properties, which were probably defined and occupied at an earlier period than the making of the roads. Another circumstance which points to the same early settlement of property boundaries is the irregularity of the ground-plans of many of the city churches. This is observable in the case of churches which from their dedication or other reasons may be pronounced of Saxon foundation. [Illustration: ALLEY NEAR THE CLOTH FAIR, SMITHFIELD.]