The First Known Christian Martyr in the Americas

From the book "West Vikings" by Farley Mowat:

"In 1059 there may have been a deliberate attempt to revisit Vinland - perhaps sparked by Gudleif's experiences. There is a record of a Celtic or Saxon priest named Jon, who had at one time worked in Iceland, having gone to Vinland or Vendland on a missionary voyage. He was subsequently reported to have been murdered by the natives there.

...

Assuming that Jon was sent to Vinland, his death should have reinforced the belief that no settlement could be established in the New World in the face of the opposition of the natives. Yet, oddly enough, the next chronological reference to the new lands is also to a missionary expedition. This one seems to have taken place in 1121 when Erik, Bishop of Greenland, is reported to have sailed for Vinland. Nothing further is known about him except that he was succeeded by a new bishop in 1124, from which we draw the conclusion that his luck was no better than Jon's.

The Vinland here referred to here was not Leif's Vinland, which was apparently never rediscovered, but was the later Vinland of the Stefansson map -- the Great Northern Peninsula of Newfoundland. It is an ironic thought that if Leif's original Vinland had been rediscovered by Karlsefni or later voyagers (with or without Leif's aid) the Norse might very well have succeeded in establishing a settlement in the New World."

Of course, Greenland is 'North America' as Great Britain is 'Europe', Japan 'Asia', or Madagascar 'Africa'. Leif's settlement in Greenland was a missionary activity of St. Olaf of Norway began in 1000 AD.