From the time when Niebuhr pointed out that there were three essentially different styles of writing, and that each style was uniformly reproduced in the same relative position in all the inscriptions, the subject had given rise to much speculation. It was at first thought that the three columns repeated the same text in the same language written in different characters.[611] Grotefend, however, recognised that the languages also were different, but he thought they were dialects closely related to each other. The first, as we have seen, he considered to be Zend, which he called the Median language; the second he thought was Parsi, or the language of the Persians; and the third another dialect of Persian, possibly Pehlevi.[612] Subsequently he changed the order of the last two, and described them respectively as resembling Pehlevi and Parsi.[613] As regards the signs, Münter thought that in the second column they were syllabic and in the third ‘hieroglyphic’; Tychsen and Grotefend thought that both had signs for vowels and consonants, which were at times replaced by an ideogram. Grotefend further saw that the second included signs for the combination of a consonant and vowel; the third he considered had no vowel signs, but used signs for the triple combination of consonant, vowel and consonant.[614] He entirely rejected the idea that either system was purely ideographic. In 1824, he prepared a Table for the third edition of Heeren, showing some words that corresponded to each other in the three languages. The inscriptions he selected were the G of Niebuhr, the inscriptions at Murgab and on the Caylus vase. These he arranged word for word in parallel columns opposite to one another. He used a full stop to indicate the combination of wedges that went to form each letter or syllable; indeed at that period it required scarcely less skill to divide the words into letters than to distinguish the words themselves. No attempt was made to assign values to the characters, and for many years no farther progress was made. In 1837 he still thought the three columns represented dialects of Old Persian, though they might not exactly correspond to Zend, Pehlevi and Parsi. The two first he considered nearer to each other as regards language; but he remarked that the two latter presented a closer resemblance to one another as regards the writing. Still he said the resemblance was by no means so close as that between the third column and the Babylonian inscriptions. He saw indeed that the writing of the third column was a mere simplification of the Babylonian; and he hazarded the useful conjecture that the writing of the second might be only an arbitrary modification of the third. He would not even yet admit that either could be, strictly speaking, described as syllabic; and he entirely rejected the idea that the third was a Semitic language.[615]