In 1170, a Welsh prince named Madog ab Owain Gwynedd sailed from Wales in search of new lands and reached America. Madog and his men are believed to have landed at Mobile Bay, Alabama and then travelled up the Alabama river constructing several forts along the way. These structures have been dated to several hundred years before Columbus and are of a similar design to Dolwyddelan Castle. An Indian tribe was discovered in the 18th century called the Mandans. This tribe were described as white men with forts, towns and permanent villages laid out in streets and squares. They claimed ancestry with the Welsh and spoke a language remarkably similar to it. Unfortunately the tribe was wiped out by a smallpox epidemic introduced by traders in 1837.