The ships stopped coming because the North Atlantic became much more dangerous as the Little Ice Age set in. The Church kept appointing Bishops for the Greenland colonies but several of those Bishops never set foot on Greenland. One major function of the Church in medieval times was tax collection with the revenues split between the king and Rome. That one dead body that Roxana mentioned was discovered on the beach when the Church sent an expedition to the 'western' colony to investigate why the tax revenues had ceased.

"The Stone Age did not end for lack of stone, and the Oil Age will end long before the world runs out of oil"

-- Sheikh Zaki Yamani