the university of pisa and the american foundation for the study of man have both excavated and restored large parts of the site and according to their carbon dating , have placed sumhurams origins in the fourth century bc , which is about six hundred years too young to have been founded by the queen of sheba , but given the symbology of the second key at the site , i think we can safely assume it is in fact much older and was probably founded or at least ruled at some stage by the queen herself .