The most pressing need of the colony was security against Iroquois raids. Before the year 1665 ended, three forts had been built on the Richelieu; one, Sorel, at its mouth, a second below the rapids at Chambly, a third at some little distance above the rapids. The line of communication was strengthened by the construction of sixteen or seventeen miles of road from Chambly to the bank of the St. Lawrence opposite Montreal, and in the following year a fourth fort was built near the northern end of Lake Champlain. [Sidenote: _Expedition of Courcelles;_] The Frenchmen determined to strike soon and hard at the Five Nations. In January, 1666, in dead of winter, Courcelles led an expedition against them up the Richelieu, by Lakes Champlain and George, on to the head waters of the Hudson river. The route, well known in after years, was unfamiliar then, and instead of turning to the west into the country of the Mohawks, the Frenchmen found themselves in the middle of February near the small Dutch settlement of Schenectady, where they were challenged as invaders of an English province, for in 1664 the Duke of York had become proprietor of New Netherland. It was news to the French commander that the valley of the Hudson had passed into British hands--unwelcome news, and would have been more unwelcome, had he foreseen the results of the change on after history. Of all events which strengthened the English cause in America against the French, the most important perhaps was the substitution of English for Dutch ownership of the present State of New York. At the time, no rupture took place between French and English, and, after an interchange of courtesies, Courcelles led his troops back to Canada, losing men through cold and privation, and {105} by the hands of the Mohawks, who dogged his retreat. He had achieved nothing, yet the daring of his venture seems to have impressed the Indians, and he had gained knowledge which was soon to tell. [Sidenote: _and of Tracy._] In September of the same year he set out again with 1,300 men, the whole commanded by Tracy in person. This time no mistake was made as to the route. The hearts of the Mohawks failed them. They fled before the invaders, leaving their strongholds empty and undefended. Each village in turn was burnt to the ground, the stores were destroyed or carried off, and, homeless and starving, the Indians were glad to make peace with the French, leaving Canada unmolested for some years to come. During those years the colony grew stronger, the administration was recast, the settlements were organized, and, beyond the line of colonization, explorers carried French influence further to the west. In 1667, Tracy returned to France. In 1671, Courcelles and Talon followed him. In 1672, Count Frontenac came out as Governor to Canada. [Sidenote: _Prominence of individual leaders in the early history of Canada._]