Rene-Robert Cavelier, Sieur de La Salle led an expedition in 1684 to establish a French colony at the mouth of the Mississippi River. However, they missed the river's mouth and settled instead at Matagorda Bay, building a settlement called Fort Saint Louis. Disease and attacks from local Native Americans caused many deaths among the colonists. La Salle attempted to get help but was killed by his own men. The few remaining colonists were later killed in an Indian attack, ending France's colony in the region. This challenged Spain's dominance as the sole European power in North America.