The first known bilingual coins of the Indo-Greeks were issued by Agathocles around 180 BCE. These coins were found in Ai-Khanoum, the great Greco-Bactrian city in northeastern Afghanistan, but introduce for the first time an Indian script (the Brahmi script which had been in use under the Mauryan empire). The coinage depict various Indian iconography: Krishna-Vasudeva, with his large wheel with six spokes (chakra) and conch (shanka), and his brother Sankarshan-Balarama, with his plough (hala) and pestle (masala), both early avatars of Vishnu. The square coins, instead of the usual Greek round coins, also followed the Indian standard for coinage. The dancing girls on some of the coins of Agathocles and Pantaleon are also sometimes considered as representations of Subhadra, Krishna's sister.