In the sacristy of the Cathedral of San Leucio is kept a bizarre "object" around which revolves the famous legend of the Dragon of Atessa. In a glass case in fact, surrounded by a grating, you can see a huge rib (about 2 meters) that tradition attributes to a dragon for a long time terror for the inhabitants of the place until S. Leucio arrived to kill him. there were two villages, Ate and Tixa, separated by a marshy and mephitic valley in which it is said a very dangerous dragon lived. Two rivers, the Osente and the Pianello (today known as Osento and Sangro), formed in fact numerous marshes that feeding an unhealthy swamp, guaranteed to the dragon its ideal environment. Its presence prevented the inhabitants of the two towns from meeting, if not at the risk of their own skins. But S. Leucio freed them from the presence of the monster. When he reached the dragon's den, he fed it for three days with meat and, when it became full, he chained it and killed it after seven days. He also kept its blood, then used by the population for therapeutic purposes, and a rib, given to the inhabitants because they kept memory of the event. A parallel tradition adds that the gigantic animal would have been found dead in front of the church of the Basilian monks, which stood at the center of one of the two villages. Anyway, the dark gorge that separated them was filled allowing them to unite in a single city, Atessa. The cathedral where the unusual relic of the rib was placed, seems to have risen in symbolic correspondence of the place where the terrible dragon had its cave. Legend has it that the dragon's den - with an entrance more than fifty palms wide - was located in Valle San Giovanni, in a very deep cave whose cavity crossed the whole Abruzzo. From that cave, in Ritifalco, there was also a forest of thorns so thick that not even birds could fly in it.