The characters on the clay tablets and cylinders, on the limestone slabs, on statues, on altars, on stone monuments, are generally known as cuneiform, because of their wedge-shaped appearance, though it may be noted at once that in their oldest form the characters are linear rather than wedge-shaped, presenting the more or less clearly defined outlines of objects from which they appear to be derived. At the time when these cuneiform inscriptions began to be found in Mesopotamia, the language which these characters expressed was still totally unknown. Long previous to the beginning of Botta's labors, inscriptions also showing the cuneiform characters had been found at Persepolis on various monuments of the ruins and tombs still existing at that place. The first notice of these inscriptions was brought to Europe by a famous Italian traveler, Pietro della Valle, in the beginning of the seventeenth century. For a long time it was doubted whether the characters represented anything more than mere ornamentation, and it was not until the close of the 18th century, after more accurate copies of the Persepolitan characters had been furnished through Carsten Niebuhr, that scholars began to apply themselves to their decipherment. Through the efforts chiefly of Gerhard Tychsen, professor at Rostock, Frederick Muenter, a Danish scholar, and the distinguished Silvestre de Sacy of Paris, the beginnings were made which finally led to the discovery of the key to the mysterious writings, in 1802, by Georg Friedrich Grotefend, a teacher at a public school in Goettingen. The observation was made previous to the days of Grotefend that the inscriptions at Persepolis invariably showed three styles of writing. While in all three the characters were composed of wedges, yet the combination of wedges, as well as their shape, differed sufficiently to make it evident, even to the superficial observer, that there was as much difference between them as, say, between the English and the German script. The conclusion was drawn that the three styles represented three languages, and this conclusion was strikingly confirmed when, upon the arrival of Botta's finds in Europe, it was seen that one of the styles corresponded to the inscriptions found at Khorsabad; and so in all subsequent discoveries in Mesopotamia, this was found to be the case. One of the languages, therefore, on the monuments of Persepolis was presumably identical with the speech of ancient Mesopotamia. Grotefend's key to the reading of that style of cuneiform writing which invariably occupied the first place when the three styles were ranged one under the other, or occupied the most prominent place when a different arrangement was adopted, met with universal acceptance. He determined that the language of the style which, for the sake of convenience, we may designate as No. 1, was Old Persian,--the language spoken by the rulers, who, it was known through