Robert Edwin Peary Sr. was an American explorer and officer in the United States Navy who made several expeditions to the Arctic in the late 19th and early 20th centuries. He is best known for, in April 1909, leading an expedition that claimed to be the first to have reached the geographic North Pole. Explorer Matthew Henson, part of the expedition, is thought to have reached what they believed to be the North Pole narrowly before Peary.