Looking at the length of the character sequences, and comparing with the names and genealogy of the Achaemenid kings as known from the Greeks, also taking into account the fact that the father of one of the rulers in the inscriptions didn't have the attribute "king", he made the correct guess that this could be no other than Darius the Great, his father Hystapes who was not a king, and his son the famous Xerxes. In Persian history around the time period the inscriptions were expected to be made, there were only two instances where a ruler came to power without being a previous king's son. They were Darius the Great and Cyrus the Great, both of whom became emperor by revolt. The deciding factors between these two choices were the names of their fathers and sons. Darius's father was Hystaspes and his son was Xerxes, while Cyrus' father was Cambyses I and his son was Cambyses II. Within the text, the father and son of the king had different groups of symbols for names so Grotefend assumed that the king must have been Darius.