The very popular Story of the Ācārya Kālakā recounts the adventures of the Śvetāmbara monk Kālakā. Emphasising the connection between religious practice and magical abilities, the story is frequently found as an appendix to the Kalpa-sūtra because it explains how Kālaka changed the date of Paryuṣaṇ. This annual festival gives a central role to the Kalpa-sūtra scripture.