Archaeological evidence suggests that a settlement had been established in the Stone Age on the present site of the Wawel Hill. A legend attributes its founding to the mythical ruler Krakus, who built it above a cave occupied by a ravenous dragon, Smok Wawelski. Many knights unsuccessfully attempted to oust the dragon by fighting it, but Krakus fed it a poisoned breakfast, which killed the dragon. He then was able to build the city on top of the hill. The bones are displayed at the entrance of the Wawel Cathedral. The first written record of the city's name dates back to 966, when a Sephardi Jewish traveller, Abraham ben Jacob, described Kraków as a notable commercial centre.