Excavation was still proceeding on the site of Nineveh. Mr. Hormuzd Rassam, himself a native of Mossul and the active assistant of Layard, was sent in 1852 by the British Museum to complete the work from which Layard had now been called away by diplomatic duties.[23] In 1853 he made a discovery which proved to be of momentous importance for Assyrian decipherment, and without which, in fact, it could never have advanced very far. He discovered the library of Nineveh with its multitudes of closely-written clay tablets, many of them containing long lists of characters, dictionaries and grammars, which have served at once to verify and to extend the knowledge of the script and language that the early decipherers had obtained. Meanwhile a careful survey of the whole country was made at the expense of the East India Company,[24] and the French Government sent out an exploring and excavating expedition to Babylonia under a young and brilliant scholar, Jules Oppert. The results of the mission, which lasted from 1851 to 1854, were embodied in two learned volumes, the first of which appeared in 1863.[25] In these Oppert showed, what Hincks and Rawlinson had already pointed out, that the peculiarities of the Assyrian syllabary were due not only to its pictorial origin but also to the fact that it had been invented by a non-Semitic people. This primitive population of Babylonia, called Akkadian by Hincks, Sumerian by Oppert, had spoken an agglutinative language similar to that of the Turks or Finns, and had been the founders of Babylonian civilization. For these views Oppert found support in the tablets of the library of Nineveh, a large part of which consists of translations from the older language into Semitic Assyrian, as well as of comparative grammars, vocabularies and reading-books in the two languages. Once more the Semitic scholars protested. There was no end to the extravagant fantasies of the Assyriologists! The learned world was comfortably convinced that none but a Semitic or Aryan people could have been the originators of civilization, and to assert that the Semites had borrowed their culture from a race which seemed to have affinities with Mongols or Tatars was an outrage upon established prejudices. The Semitic philologist was more certain than ever that Assyrian decipherment was the folly of a few “untrained” amateurs, and could safely be disregarded. But the little band of Assyriologists pursued their labours undisturbed. In 1855–6 Hincks published a most remarkable series of articles in the _Journal of Sacred Literature_, in which the various forms of the Assyrian verb were analyzed and given once for all. The work has never had to be repeated, and the foundations of Assyrian grammar were solidly laid. A few years later (in 1860) a complete grammar of the language was published by Oppert. The initial stage of Assyrian decipherment was thus at an end.