What I've read is that there were Irish monastic colonies on Iceland before the
Norwegians came. Also, that the Viking Icelanders captured many women to be
their wives. There are also linguistic borrowings from Old Irish in Old
Icelandic, evidence perhaps of a close contact between the peoples.
I've also read that it was the Irish wives of the Icelanders that converted them
I hope it helps. You might look for E.V. Gordon's book *An Introduction to Old
Norse.* He covers some of this in his introduction.