I know very little about Viking or medievel artifacts. The European members would be more helpful. It may be old but it would seem to me too thick and heavy for a dagger or spear and no way to attach it to a pole. I can only guess what it is. It doesnt look broken so maybe a coal miners wedge, harvester tooth, clock weight, sounding weight or log splitter as mentioned..
Its better to add additional pics to the same thread. It seems you have 3 threads on the same object! This is confusing and senseless. Its more bemeficial to keep all the opinions on one page. Interesting find.