The first publication of a seal with Harappan symbols dates to 1875, in a drawing by Alexander Cunningham.[6] Since then, over 4,000 inscribed objects have been discovered, some as far afield as Mesopotamia. In the early 1970s, Iravatham Mahadevan published a corpus and concordance of Indus inscriptions listing 3,700 seals and 417 distinct signs in specific patterns. He also found that the average inscription contained five symbols and that the longest inscription contained only 14 symbols in a single line.[7] He also established the direction of writing as from right to left.[8]