Belgian explorer and Franciscan missionary priest who is presumed to be the first European to have seen and described Niagara Falls (in his book A New Discovery of a Vast Country in America, published in 1697). In 1675, Father Hennepin traveled to Quebec as a missionary among the Iroquois Indians. In 1678, he joined the expedition of French explorer Robert Cavelier, Sieur de La Salle, traveling through the Great Lakes to the Illinois River. Hennepin was sent by La Salle on a voyage via canoe to explore the upper Mississippi River, where in 1680 he discovered the Falls of Saint Anthony (in present-day Minnesota) while a captive of Sioux Indians. Known for exaggerating his explorations in writings such as his book A New Voyage (1698), the priest fell into disgrace in his later years and the end of his life remains a mystery.