Upon the recovery of Canada by the French, Nicolet returned to Quebec, probably early in 1633. In June, 1634, Champlain sent him on an exploring expedition westward--partly in the hope of finding the "sea of China" which was at that time supposed to lie not far west of the regions of America then known, and thereby discovering the long-looked-for short passage to Asia; partly to become acquainted with the savage tribes lying beyond the "Mer douce" (Lake Huron), and to extend the French trade for peltries. Upon this trip (accompanying Brébeuf as far as Allumettes Island), Nicolet went to his old abode, Lake Nipissing. Thence, with a bark canoe, and an escort of seven Hurons, he voyaged by French River into Lake Huron, and northward to St. Mary's Straits and Mackinac; and thence by Lake Michigan, Green Bay, and the Fox River, as far as a village of the Mascoutins, probably in what is now Green Lake county, Wisconsin. He was thus the first white man who, so far as is recorded, had entered this region. From the Mascoutin village, he journeyed southward to what is now Northern Illinois,--afterwards returning to Canada by the same route on which he had set out; he reached Quebec early in the autumn of 1635. This notable voyage was generally supposed to have occurred in 1639, until Sulte advanced the theory, in _Mélanges d'Histoire et de Littérature_ (Ottawa, 1876), pp. 426, 436, that it must have been in 1634-35--a theory apparently verified by Butterfield, in his painstaking _Discovery of the Northwest by Jean Nicolet_ (Cincinnati, 1881). Nicolet, after his return to Canada, resumed his employment (begun in 1633) as clerk and interpreter at Three Rivers. Oct. 7, 1637, he married Marguerite (then aged eleven years), second daughter of Guillaume Couillard. Probably about this time, he obtained, jointly with his brother-in-law, Le Tardif (see vol. v., _note_ 49), the estate of Belleborne (so named from the brook of Belleborne, which traverses the "plains of Abraham"). In 1641, the Iroquois having attacked the Algonkins in the near vicinity of Three Rivers, Nicolet, with the Jesuit Ragueneau, attempted, but with little success, to turn aside the hostile savages. Nicolet died Oct. 29, 1642, being drowned at Sillery; he left but one child, Marguerite, who in 1656 married Jean Baptiste le Gardeur. Full accounts of Nicolet and of his discoveries are given in Butterfield's monograph, and by Sulte, _ut supra_; also in Jouan's "Jean Nicolet," and Butterfield's bibliography of the subject, _Wisconsin Historical Collections_, vol. xi., pp. 1-25. Cf. also Sulte's "Notes on Jean Nicolet," _Id._, vol. viii., pp. 188-194. Nicolet river and lake, in Wolfe county, Que., are named for this noted explorer; the river had been, until about 1640, known as the St. Jean.