Ever since it surfaced in 1957, the Vinland Map has been controversial. Id authentic, it proves that Vikings found North America before Christopher Columbus. Others argue that it is instead the work of a 20th-century counterfeiter.

Now the results of two new studies are adding further fuel to the debate. A report published in the journal Analytical Chemistry concludes that the map's ink has modern roots; researchers writing in the August issue of the journal Radiocarbon, on the other hand, say that the parchment dates back to 1434.