These Watermen (Nautae) seem from early days to have been an important guild, first as carriers of merchandise and later as an administrative body. In the twelfth century the band was called the Brotherhood of Water Merchants, and its head the Provost of the Water Merchants, a name given in shortened form--Provost of the Merchants--to the first magistrate of the city up to the time of the Revolution at the end of the eighteenth century. Even to-day such of the duties of the Prefect of the Seine as apply not to the Department of the Seine but to the city of Paris alone are comparable to those of the Provost of the Merchants. From the seal of the Nautae, a boat, has developed the present coat of arms of the City of Paris. It was about the middle of the third century that the altar to greatest Jupiter began to be deserted by its worshipers, for it was then that Saint Denis came to Paris to preach the new religion, and with his coming and the Emperor Constantine’s conversion Christian churches began to be built. Even the martyrdom of Saint Denis, who, according to Gregory of Tours, “ended his earthly life by the sword,” was no check to believers. Legend has it that his head was stricken off on Montmartre, the hill towering above Paris on the north, and to-day crowned by the pearl-white dome of the basilica of the Sacré Coeur gleaming, mysterious, through the city’s eternal haze. The hill’s name has been said to mean “Mount of Mars,” because of a pagan altar raised upon its summit, or “Mount of the Martyr,” referring to the death of Saint Denis. Either derivation may be defended, and neither contradicts the story that the holy Bishop of Paris, decapitated, picked up his head and carried it for several miles before a kindly-disposed woman offered him burial. Over his remains a chapel was raised, restored about two centuries later by Sainte Geneviève, and replaced in 630 by the basilica which Dagobert I (602-638) erected to house fittingly that most holy relic, the head of the saint. The existing church was begun about five hundred years later by Suger, the minister of Louis VI who adopted the _oriflamme_ of Saint Denis as the royal standard of France. The flag hung above the altar and was used only when the king went into battle himself. Since the English victory on the field of Agincourt (1415) it has not left the church. The banner (in replica) stands to-day in the choir behind and to the left of the high altar. Throughout the church are the tombs of the Kings of France from Dagobert to Louis XVIII--twelve centuries of royal bones.