So closely does Paris cling to her ancient traditions that even in the twentieth century the schools and their students are removed but a few yards from their medieval location. The students of to-day, too, have their own traditions of dress and behavior which mark them as inhabitants of the “Latin Quarter” even if they are kodaked at Versailles on a holiday afternoon. They assume for themselves now privileges which Philip Augustus encouraged them to take by making them free from the regulations which the other citizens obeyed and subject only to the ecclesiastical tribunal. This difference of attitude caused many riots in the thirteenth century and they break out afresh in the twentieth with a frequency which helps to occupy any idle moments of the city police. So great were the attractions of Paris offered not only to students but to merchants that the population of the city grew to one hundred and twenty thousand under Philip’s rule. The populous section on the south or left bank of the river was matched by another on the north, chiefly inhabited by merchants and artisans, and both of them were larger than the original Cité on the island. The Cité was the administrative and ecclesiastical center, for the king’s palace was not his only residence but also a palace of justice, and crowded into the limits set by the Seine were so many churches that one of them served a parish of only twenty houses. The northward growth of the city encroached upon the Halles as it had upon the cemetery of the Innocents, and Philip recognized the necessity of enclosing and roofing the markets. Such utilities as public ovens, too, which had been a monopoly of some of the religious houses, he opened to the citizens at large. He also instituted a water supply, which, though far from ample, since it allowed only two quarts a day for each inhabitant, was an earnest of good intentions. The original tower of the Louvre seemed to Philip a good nucleus for an enlarged fortification which should be at the same time a palace to which he might withdraw from the palace in the crowded Cité. Around the old donjon he built a rectangular fortress, its short end lying along the river, its entrance defended by another huge tower whose work of protection was reinforced by smaller towers, by a surrounding wall, and by a moat. Down beneath the treasures of to-day’s Louvre and out under the courtyard still run passages of this old building. They twist and turn within walls of rough masonry and inflame the imagination with thoughts of adventurous possibilities, of plots and prisoners and escapes, until they land the wanderer of a sudden in the coal bin of the hopelessly up-to-date furnace that heats the Hall of the Caryatides.