Many Rus epic poems, called Bylinas, prominently featured stories about these heroes, as did several chronicles, including the 13th century Galician–Volhynian Chronicle. Some bogatyrs are presumed to be historical figures, while others, like the giant Svyatogor, are purely fictional and possibly descend from Slavic pagan mythology. The epic poems are usually divided into three collections: the Mythological epics, older stories that were told before Kiev-Rus was founded and Christianity was brought to the region, and included magic and the supernatural; the Kievan cycle, that contains the largest number of bogatyrs and their stories(IIya Muromets, Dobrynya Nikitich, and Aloysha Popovich); and the Novgorod cycle, focused on Sadko and Vasily Buslayev, that depicts everyday life in Novgorod.