NAIN (Lewis Sebastian de), one of the most learned and judicious critics and historians France has produced, was the son of a master of the requests, and born at Paris in 1637. At ten years old he went to school at Port Royal, and became one of the best writers of that institution. Sacy, his intimate friend and counsellor, prevailed with him in 1676 to receive the priesthood; which, it seems, his great humility would not before suffer him to aspire to. This virtue he seems to have possessed in the extreme; so that Bossuet, seeing one of his letters to father Dami, with whom he had some little dispute, besought him merrily "not to be always upon his knees before his adversary, but raise himself now and then up." He was solicited to push himself in the church, and Buzanval, bishop of Beauvais, wished to have him for his successor: but Nain, regardless of dignities, wished for nothing but retirement. In this he did indeed most effectually bury himself; and, joining the mortifications of a religious life to an indefatigable pursuit of letters, he wore himself entirely out, so as to die in 1698, aged 61, though he was formed for a longer life. His principal works are, 1. Memoirs on the ecclesiastical history of the six first ages of the church, 16 vols. 4to. 2. The history of the emperors, 6 vols. 4to. These works are deduced from original sources, and composed with the utmost fidelity and exactness.