It is, however, to George Frederick Grotefend, of Hanover, that the discovery of the key which has unlocked the secrets of cuneiform literature is really due. On September 4, 1802, he read before the Royal Society of Göttingen a Memoir, in which he announced his discovery of the names of certain Achaemenian kings in the cuneiform inscriptions, and explained the method by which he had arrived at his results. By a curious coincidence it was at the same meeting of the Society that Heyne described the first efforts that had been made towards deciphering the Egyptian hieroglyphics. Grotefend first showed convincingly that the inscriptions must be read from left to right, a portion of a word which ends a line on the right side in one of the texts beginning the next line on the left side in a duplicate copy of it. He next pointed out that the analogy of the Sassanian inscriptions, which had just been deciphered by de Sacy, indicated that the Persepolitan texts must commence with the names of the kings who had erected the monuments, followed by their titles, and that a comparison of the texts one with another made it pretty evident that such was actually the case. In this way he succeeded in finding (like Münter before him) the word for 'king,' and in addition to this the royal names preceding it. Those on the Persepolitan monuments represented a father and a son, though in certain cases the father added his own father's name, but without the royal titles. Thanks to the classical writers, it was known that the monuments were of Achaemenian origin, and the names of the Achaemenian kings had also been preserved. It only remained to fit them to the characters in the cuneiform texts. Hystaspes, Darius, and Xerxes alone suited, since Cyrus was too short and Artaxerxes too long; moreover, the letters _a_, _r_, and _sh_, in the names of Darius and Xerxes appeared in their right places if these names were adopted. So, too, did _a_ and _sh_ in the name of Hystaspes. Such a coincidence was sufficient to prove that Grotefend was right in his guess that the words in question represented proper names, for guess it was, though founded on strong probability and scientific induction. He had noticed that two of the names (those of Darius and Xerxes) occurred separately on two particular groups of monuments, whereas the word which followed them was always the same. It was natural to conclude that the latter word denoted 'king,' while those which preceded it were proper names.