There is a story, likely apocryphal, that he named it "Disappointment River", but eventually it was named after him. No European reached its mouth again until Sir John Franklin on 16 August 1825 during the 1825–1827 Mackenzie River expedition. The following year he traced the coast west until blocked by ice while John Richardson followed the coast east to the Coppermine River. In 1849 William Pullen reached the Mackenzie from the Bering Strait. In the following decades the North West Company established forts on the river, the precursors of present-day settlements such as Fort Simpson (formerly Fort of the Forks). A lucrative fur trade was carried out, as the Mackenzie basin teemed with beaver and muskrat. However, the short summer and harsh winter conditions limited trappers' activities. During the late 19th century Fort Simpson was regional headquarters for the Hudson's Bay Company. The first fur trappers were native, but starting in the 1920s increasing numbers of European trappers entered the region. Beaver and muskrat populations were heavily depleted, especially in areas around and south of Great Slave Lake. Catholic missionary Henri Grollier founded missions at Fort Simpson, Fort Norman and Fort Good Hope between 1858 and 1859. During the late 19th century and early 20th century epidemics of introduced European diseases swept through Indigenous communities along the river, and thousands of native people lost their lives. One particularly severe influenza in 1928 killed as many as one in ten native people along the Mackenzie River. Fort Providence lost 20 percent of its population, and some smaller villages and camps were completely wiped out. Steamboat service on the Mackenzie River began in the 1880s, and the number of vessels surged in the early 1900s as the Klondike Gold Rush brought a wave of prospectors to the Yukon. The Mackenzie River was one of the main routes into the northern interior, with sternwheelers transporting passengers, domestic supplies and industrial goods from as far upstream as the Athabasca River all the way to the delta, though with several areas such as the huge rapids on the Slave River requiring portages. The route taken by gold seekers started in Edmonton and followed the Athabasca, Slave and Mackenzie Rivers as far as the Peel River, then up the Peel and its tributary the Rat River to the headwaters of the Porcupine River, which flows to the Yukon River. Many who attempted the journey died along