 This replacement of human victims with effigies is attributed to Padmasambhava, a Tibetan saint of the mid-8th century, in Tibetan tradition.Nevertheless, there is some evidence that outside of lamaism, there were practices of tantric human sacrifice which survived throughout the medieval period, and possibly into modern times.The 15th-century Blue Annals, a document of Tibetan Buddhism, reports upon how in 13th-century Tibet the so-called "18 robber-monks" slaughtered men and women in their ceremonies.