The eldest, who bore his father’s name and possessed many of his traits, inherited the seigneury. Soon he made it one of the most valuable properties in the whole colony. The old manor-house gave way to a pretentious chateau flanked by four imposing towers of solid masonry. Its dimensions were, as such things went in the colony, stupendously large, the structure being about two hundred feet in length by one hundred and seventy in breadth. The great towers or bastions were loopholed in such way as to permit a flanking fire in the event of an armed assault; and the whole building, when viewed from the river, presented an impressive facade. The grim Frontenac, who was not over-given to eulogy, praised it in one of his dispatches and said that it reminded him of the embattled chateaux of old Normandy. Speaking from the point of view of the other seigneurs, the cost of this manorial abode of the Longueuils must have represented a fortune. The structure was so well built that it remained fit for occupancy during nearly a full century, or until 1782, when it was badly damaged by fire. A century later still, in 1882, the walls remained; but a few years afterwards they were removed to make room for the new parish church of Longueuil.
Le Moyne did more than build an imposing house. He had the stones gathered from the lands and used in building houses for his people. The seigneur’s mill was one of the best. A fine church raised its cross-crowned spire near by. A brewery, built of stone, was in full operation. The land was fertile and produced abundant harvests. When Catalogne visited Longueuil in 1712 he noted that the habitants were living in comfortable circumstances, by reason of the large expenditures which the seigneur had made to improve the land and the means of communication. Whatever Charles Le Moyne could gather together was not spent in riotous living, as was the case with so many of his contemporaries, but was invested in productive improvements. That is the way in which he became the owner of a model seigneury.