Today I read a strange story about who discovered the Americas. It is about that Turkish President Recep Tayyip Erdogan said that Muslims, not Columbus, discovered Americas. The assumed discovery should have happened in the year 1178 in the Gregorian calendar.
Well, in my history book it goes like this:
1st the indigenous peoples of the Americas, sometimes called Indians (as opposed to cowboys), found that land by crossing the Bering Strait thousands of years ago.
2nd there is much speculation about that someone else crossed the oceans. Only archaeological evidence (so far) is that the Vikings were on Newfoundland of the coast of Canada at a place today called L’Anse aux Meadows. That happened around year 1000 in the Gregorian calendar. (By the way they came from Greenland, that geographically is a part of the Americas).
3rd Christopher Columbus and his crew arrived in the Americas in the year 1492 in the Gregorian calendar.
That is the data quality part of the story. The rest is information quality.
Liliendahl on Data Quality 
Henrik, you forgot about the Irish St. Brendan who, it is claimed, sailed from Ireland to the Americas long before Columbus (http://en.wikipedia.org/wiki/Brendan#The_Voyage_of_Saint_Brendan). And the Chinese, who might have reached the Americas before Columbus. http://www.livescience.com/7002-map-fuels-debate-chinese-sail-world.html
And, from a Data Quality perspective, it’s worth remembering that Columbus never admitted he had reached a new continent, insisting he had reached the East Indies. http://en.wikipedia.org/wiki/Christopher_Columbus
Well Daragh, the day they find a 1500 hundred year old jar with a Guinness inscription on the American coast St. Brendan can claim his 2nd place.
And then there’s Amerigo Vespucci: http://www.livescience.com/42510-amerigo-vespucci.html
Indeed Joy, that guy knew where he was as opposed to Columbus as Daragh points out.