He seized these men, it appears, partly because he wanted hostages and had good reason to fear that the Indians meditated a treacherous attack on his ships before they could get away.

He also wished for native witnesses at Court, when he reached France, to testify to the truth of his discoveries, and even more to convince the King of France that there was great profit to be obtained from giving effect to Cartier's explorations.

The chief, Donnacona, was full of wonderful stories of the Saguenay region, and of the great lakes to the northwards of Quebec.

Probably he was only alluding to the wealth of copper now known to exist in northern Canada, but to Cartier and the other Frenchmen it seemed as though he spoke of gold and silver, rubies, and other precious stones.
Donnacona's people howled and wept when their chief was seized; but Cartier obliged the chief to reassure them, and to say that the French had promised to bring him back after he had paid a visit to their great king, who would return him to his country with great presents.
As a matter of fact, not one of these Indians rapt away by Cartier ever saw Canada again.

But this was not the fault of Cartier, but of the distractions of the times which turned away the thoughts of King Francis I from American adventures.