The promoting cause for this forward movement was again the dream of opening up a North-West Passage. The hold this had upon the French we see was less than that upon Frobisher, James, Middleton, or Dobbs among the English. Speaking of the French interest in the scheme, Pierre Margry, keeper of the French Archives in Paris, says: "The prospect of discovering by the interior a passage to the _Grand Océan_, and by that to China, which was proposed by our officers under Henry IV., Louis XIII., and Louis XIV., had been taken up with renewed ardour during the Regency. Memorial upon memorial had been presented to the Conseil de Marine respecting the advisability and the advantage of making this discovery. Indeed, the Père de Charlevoix was sent to America, and made his great journey from the north to the south of New France for the purpose of reliably informing the Council as to the most suitable route to pursue in order to reach the Western Sea. But the ardour which during the life of Philip of Orleans animated the Government regarding the exploration of the West became feeble, and at length threatened to be totally extinguished, without any benefit being derived from the posts which they had already established in the country of the Sioux and at Kaministiquia." "The Regent, in choosing between the two plans that Father Charlevoix presented to him at the close of his journey for the attainment of a knowledge of the Western Sea, through an unfortunate prudence, rejected the suggestion, which, it is true, was the most expensive and uncertain, viz. an expedition up the Missouri to its source and beyond, and decided to establish a post among the Sioux. The post of the Sioux was consequently established in 1727. Father Gonor, a Jesuit missionary who had gone upon the expedition, we are told, was, however, obliged to return without having been able to discover anything that would satisfy the expectations of the Court about the Western Sea." At this time Michilimackinac was the depôt of the West. It stood in the entrance of Lake Michigan--the Gitche Gumee of the Indian tribes, near the mouth of the St. Mary River, the outlet of Lake Superior; it was at the head of Lake Huron and Georgian Bay alike. Many years afterwards it was called the "Key of the North-West" and the "Key of the Upper Lakes." A round island lying a little above the lake, it appealed to the Indian imagination, and, as its name implies, was likened by them to the turtle. To it from every side expeditions gathered, and it became the great rendezvous. At Michilimackinac, just after the arrival of Father Gonor, there came from the region of Lake Superior a man whose name was to become illustrious as an explorer, Pierre Gaultier de Varennes, Sieur de la Verendrye. We have come to know him simply by the single name of Verendrye.