Thor's Hammer.

Archaeologists have discovered a lead Thor’s hammer amulet dating to the late 10th century in Ysby in southwestern Sweden’s Halland province. The hammer was unearthed at the site of future housing construction. 

These were popular accessories in the Viking era, worn as apotropaic amulets, calling on the protective power of Thor to ward off evil. About a thousand of them have been found in Scandinavia, the UK, Russia and the Baltic countries. When this one was being worn, the Halland area was beginning to convert to Christianity. A pendant like this had religious significance beyond its purported warding powers, because it was unmistakable symbol of adherence to Form Sidr (meaning “the old way” ie, the traditional Nordic gods) as opposed to the new way of Christianity.

Via the always good History Blog.