First found in Brittany, where they are recorded as an ancient family with lands, manors and estates.

French settlers came early to North American, following in the wake of the explorers, and creating New France. Quebec City, founded in 1608 by Sam UEL de Champlain is said to have been the first American site founded as a permanent settlement, rather than as just a commercial outpost. But emigration was slow, in 1643, 109 years after the first landings by Cartier, there were only about 300 French people in Quebec, and by 1663, when the region was officially made The Royal Colony of New France, by Louis XIV, there still only around 500 settlers. Over 2,000 would arrive during the next decade. Early marriage was desperately encouraged amongst the immigrants. Youths of 18 took fourteen-year-old girls for their wives. The fur trade was developed and attracted immigrants, both noble and commoner from France. By 1675, there were around 7000 French in the colony, and by that same year the Acadian presence in Nova Scotia, New Brunswick and Prince Edward Island had reached 500. In 1755, 10,000 French Acadians refused to take an oath of allegiance to England and were deported to Louisiana. Despite the loss of the Colony to England, the French people flourished in Lower Canada. Among settlers to North America of the Cadeau surname were François Cadieu, 17; who settled in Louisiana in 1719; Pierre Cadieux, who married Marguerite Menard in 1697 in Boucherville, Quebec; Jacques Cadieux, who married Marie Viau in 1731 in Longueuil, Quebec.

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