Wikipedia
Öndvegissúlur , or high-seat pillars, were a pair of wooden poles placed on each side of the high-seat—the place where the head of household would have sat—in a Viking-period Scandinavian house.
According to descriptions in Landnámabók and several sagas, written long after settlement, some of the first settlers threw high-seat pillars they had brought with them from Norway overboard once in sight of land. They then established their permanent farms at the site where the pillars washed ashore. The first farm established in Iceland, located where the capital, Reykjavík, stands today, was founded using this method.
One saga refers to a high-seat pillar having been carved with an image of the god Thor, and Icelandic saga Eyrbyggja saga relates that when Þórólfur Mostrarskegg (Thorolf Most-Beard) constructed a temple after reaching Iceland, the high seat pillars had reginnaglar (Old Icelandic "god-nails" or "power-nails") in them. Otherwise very little is known about what they might have looked like.