Madoc (Madog or Madawg) ap Owain Gwynedd was a Welsh prince who, according to legend, discovered America in 1170, over three hundred years before Christopher Columbus's voyage in 1492. Madoc has been the subject of much historical speculation, but most scholars doubt that Madoc ever made a trip to North America, and some doubt the prince existed at all.
A later development in the legend claimed the settlers were absorbed by groups of Native Americans, and their descendants remained somewhere on the American frontier for hundreds of years. The first to report an encounter with a Welsh-speaking Indian was the Reverend Morgan Jones, who was captured in 1669 by a tribe of Tuscaroras called the Doeg. The chief spared his life, however, when he heard Jones speak Welsh, a tongue he understood. Jones lived with the Doeg for several months preaching the Gospel in Welsh, and returned to the British Colonies where he recorded his adventure in 1686.
A number of later travellers claimed to have found the Welsh Indians, and one even claimed the tribe he visited venerated a copy of the Gospel written in Welsh. Stories of Cymric Indians became popular enough that even Lewis and Clark were ordered to look out for them, and folklore has long claimed that Louisville, Kentucky was once home to a colony of Welsh-speaking Indians. 18th century Missouri River explorer John Evans of Waunfawr, Wales took up his journey in part to find the Welsh-descended "Padoucas" or "Madogwys" tribes. The legend was not apparently restricted to whites; in 1810, John Sevier, the first governor of Tennessee, wrote to his friend Major Amos Stoddard about a conversation he had had with the old Cherokee chief Oconostota concerning ancient fortifications built along the Alabama River. The Chief said the forts were built by the white people who had once lived in the area as protection against the ancestors of the Cherokee. They were called "Welsh" and their leader was "Modok". How much of the original conversation, which was supposed to have occurred in 1782, was accurately related in Sevier's letter in 1810 is of course debatable.
In the early tales, the white Indians' specific European language ranged from Irish to Portuguese, and the tribe's name varied from teller to teller (often, the name was unattested elsewhere), but later versions settled on Welsh and the Mandan people, who differed strikingly from their neighbors in culture, language, and appearance. The painter George Catlin suggested the Mandans as descendants of Madoc and his fellow voyagers in North American Indians (1841); he found the round Mandan Bull Boat similar to the Welsh coracle, and thought the advanced architecture of Mandan villages must have been learned from Europeans (advanced North American societies such as the Mississippian and Hopewell cultures were not well known in Catlin's time). Supporters of this theory have drawn links between Madoc and the Mandan mythological figure Lone Man, who, according to one tale, provided his people with homes during and after a great deluge.