Other scholars, such as Erich Frauwallner and Richard Gombrich, believe that the missions mentioned in the Sri Lankan tradition are historical. According to these scholars, a part of this story is corroborated by archaeological evidence: the "Vinaya Nidana" mentions names of five monks, who are said to have gone to the Himalayan region; three of these names have been found inscribed on relic caskets found at Bhilsa (near Vidisha). These caskets have been dated to the early 2nd century BCE, and the inscription states that the monks are of the Himalayan school. The missions may have set out from Vidisha in central India, as the caskets were discovered there, and as Mahinda is said to have stayed there for a month before setting out for Sri Lanka.