The Vérendrye brothers were the first Europeans to cross the northern Great Plains and see the Rocky Mountains (1742–43). We know very little about their journey. All we know comes from a journal found in the French archives in 1851, another document in the French archives and a lead plate found buried near Pierre, South Dakota. The journal is difficult to interpret. The mountains they saw were probably the Big Horn Mountains of Wyoming, but they could have been the Black Hills or the Laramie Mountains. The journal states the trip may made by the "Chevalier Verendrye and one of his brothers" who are otherwise unidentified. Most likely the Chevalier was Louis-Joseph Gaultier de La Vérendrye and the brother was François de La Vérendrye but we cannot be sure.