Several French speculators, in succeeding years, thought to make money out of supposed mines of gold, silver, lead, and copper along the upper waters of the Mississippi. Some of them came over from France with bands of miners and little companies of soldiers to guard them; but, like Le Sueur, they spent most of their time and money in exploration, not content with those lead mines that were well known to exist, and invariably left the country in disgust, their money and patience exhausted. Now and then a more practical man came quietly upon the scene, and seemed well satisfied with lead when he could not find gold; most of such miners were French, but a few were Spanish, for Spain then owned all the country lying westward of the Mississippi River. Occasionally the French commandant at Mackinac or Detroit would come to the mines, and with the aid of his soldiers and the Indians, get out a considerable quantity of the ore, and take it home with him in his fleet of canoes; or a fur trader would do the same, for the purposes of his own trade with the savages. The little French village of Ste. Geneviève, near St. Louis, had become, by the opening of our Revolutionary War, a considerable lead market, from which shipments were made in flatboats and bateaux down the Mississippi to New Orleans, or up the Ohio to Pittsburg. Lead was, next to peltries, the most important export of the Upper Mississippi region, and throughout the West served as currency. During the Revolutionary War, the British were at first in command of the upper reaches of the great river, and guarded jealously the approach to the lead mines, for bullets were necessary to the success of the fast growing Kentucky settlements; American military operations against the little British garrisons at Vincennes, Kaskaskia, Cahokia, and Detroit would be powerless without lead. Gradually the influence of the American fur trade grew among the Indians, and it was not long before the Americans in the West were able to obtain through them all the lead they wanted. Toward the close of the war, Julien Dubuque, a very energetic French miner, bought up large claims from the Spaniards, in Missouri and Iowa, and for about a quarter of a century was the principal man in the lead region. He was remarkably successful in dealing with the Indians, whom he employed to do the principal work. His mining and trading operations were not confined to the Spanish side of the river, but were carried on in American territory as well, and his influence with the savages for a time prevented American miners and fur traders from obtaining a foothold.