 An inscription dates the vault to 1435-1436 and says that Khalilullah I built it for his mother Bika khanim and his son Farrukh Yamin.His mother died in 1435 and his son died in 1442, at the age of seven.Ten more tombs were discovered later on; these may have belonged to other members of the Shah's family, including two more sons who died during his own lifetime.