The Vinland Map
Uncertain. The parchment itself radiocarbon-dates to circa 1411-1468 and is genuinely medieval. The ink and drawing on it were added later: they copy specific errors found only in an 18th-century (1782 or 1783, sources differ) facsimile reprint of Andrea Bianco's 1436 world map, which sets a firm earliest possible date, and the ink's titanium dioxide pigment (anatase) was not manufactured in its synthetic rounded form before roughly the 1920s. A chemical wash or coating applied to the parchment has also been read as bearing trace fallout markers that would place that treatment no earlier than the early 1950s. Yale's working position since 2021 is that the map was drawn in the 20th century on a genuine but unrelated piece of 15th-century parchment. - Ink (a black carbon overlay on a yellow anatase-bearing line, bound in a collagen/gelatin medium) drawn onto a genuine 15th-century parchment bifolium