There was a group that came from Wales 600 years before Columbus and settled in the Mississippi river areas.
They may have visited this area too and brought sickness to the natives.
Read more.
The Colmbia Encyclopedia:
" MADOC OR MADOG (Madoc ap Owain Gwynedd) fl. 1170?, quassi-historical Welsh prince. According to Welsh legend, Madoc, said to be a son of Owain Gwynedd, discovered America 300 years before Columbus. Witnesses' accounts of finding supposedly Welsh-speaking Native Americans have served to keep alive the story, which is otherwise unsupported by evidence. He is the subject of Robert Southey's Madoc."
Wikipedia Encyclopedia:
"MADOC (MADOC AP OWAIN GWYNEDD) was purported Welsh prince who, some believe, discovered America in 1170, over three hundred years before Christopher Columbus's voyages in 1492.
"His father, King Owain Gwynedd ap Gruffydd had at least 13 children from his two wives, and, it is said, several more born out of wedlock, among them Madoc and his brother Riryd. They were living at a time when Wales was born by strife and civil war.
"Upon his father's death in 1170, as usual fighting broke out among the possible successors, Madoc, disheartened, set sail to explore the western wea, found what is described as a distant and abundant land, and returned to Wales to recruit settlers; he then sailed west a second time for good. Madoc's landing place has been suggested by some theories to be Mobile Bay in what is now Alabama in the United States.
"There is some speculation that these early Welsh settlers had later been absorbed by American Natives, and that members of the Mandan Tribe, strikingly different in culture, language and appearance, might be descendants of Madoc and his fellow voyagers.
" Possibly the first written account of Madoc's story is found in a history of Wales published in 1584 by David Powell (1552?-1598?).
"Another account comes from John Dee in 1577. Dee claimed that King Arthur had won a vast empire in the North Atlantic and that the voyages of Madoc had confirmed the title of the Welsh to those territories. By the age of Elizabeth I of England, Dee asserted, they were under the sovereignty of the queen as successor to the Welsh princes. Basically Dee was making the assertion as a priority claim on North America for Great Britain over those of other nations.
"Recent research by Alan Wilson, Baram Blackett and Jim Michael suggests an even earlier date (and a different person) behind the myth. Using radiocarbon dating and DNA profiling methods on artifacts and human remains found in the US Midwest and in Wales, they claim to have found strong indications that the Khumric (Welsh) Prince Madog Morfran ap Meurig ("the cormorant"), brother of King Arthur II, left Wales in the aftermath brought by heavy destruction due to debris falling from a comet (562 CE), and arrived in North America during the 6th century and set up colonies.
"Several local guest houses and pubs are called Prince Madoc in his memory. However, according to other sources, the towns of Porthmadoc (Porthmadog, Port Madoc) and Tremadoc, county Gwynedd, Wales, are named after the North Welsh industrialist and Member of Parliament, William Alexander Maddock (1773-1828). The Prince Madog, the University of Wales' new research vessel, set sail on 2001-07-26 on her maiden vgoyage.
" Madoc - A Mystery is a long, multi-layered poem by Paul Muldoon (which won him the Geoffrey Faber Memorial Prize), exploring the Madoc legend, mostly through association with Samuel Taylor Coleridge and Robert Southey, who (in 1794) had played with the idea of going to America to set up an "ideal state."
OTHER ARTICLES:
http://olivercowdery.com/texts/1805sout.htm
"Madoc" by Robert Southy, 1805 London
http://www.rense.com/genderal28/weks.htm
"Did the Welch Discovery Ameria During the 6th Century?"
http://www.100megsfree4.com/farshores/a04madoc.htm
"Ancient Mysteries: Welsh prince Madoc in america Discovery Row"
Leading experts on King Arthur, say the south Walian prince Madoc Morfran sailed in 562 AD and made the discovery.
http://www.tywythteg.com/fortmount/Ftmount.html
"Georgia's Fort Mount and Prince Madoc of Wales"
http://www.where-can-i-find.com/wales/history/madoc.htm
"Where Can I Find Information on Prince Madoc and the Discovery of America?"
http://www.madoc1170.com/home.htm
"Madoc: Were the Welsh the first European Americans?"
http://home.att.net/~dana.olson?
"Prince Madoc and the White Indians"
http://www.100megsfree4.com/farshores/a04madoc.htm
"Was America Discovered in 1170 by Prince Madoc ab Owain Gwynedd of Wales?"
http://www.freewebs.com/brandenburg_stone
"The Brandenburg [KY] Stone and Prince Madoc"
http://freepages.genealogy.rootsweb.com/~maddoxetc/
Click on Welsh Origins on the left column