It is stated that Leif Ericsson was Christian, when he sailed to Canada, in the year 1,000 AD.
It is known that Greenland was settled by Norse (including both Norwegians and Icelandic) who arrived in a fleet of 25 ships about 985 a.d. The conversion to Christianity took place some years after that, whether before the turn of the century voyage and brief settlement in Vinland (modern Newfoundland) or after, there is no definite archaeological evidence.
The earliest known church which was has been discovered was built was about a century later, though most archaeologists believe it was build on the site of an earlier temporary structure some years earlier.
Their Icelandic homeland doesn't provide many clues either, as the Hiberno-Scottish monks were gone by 874 ad, when the first Norse arrives. Quite likely conversion was a gradual process which happened early in the 11th century by trade contacts between their Icelandic cousins at the descendants of the Hiberno-Scottish peoples of northern Scotland and the Orkney's who had abandoned their Iceland settlement years or even decades before the first Norse arrived in 874 ad but still had seafaring and trading skills almost equal to the vikings.
Do you know of any hard evidence that Leif Ericsson was Christian, or is it mostly anecdotal?