The reign of the third Mauryan emperor Ashoka (272-323 BC) transformed Buddhism. Although it had been expanding slowly since its foundation in the sixth century, Buddhism was still rooted in the Puratthima (Eastern Tract) of the middle-lower Ganges from which it had arisen. By the end of Ahoka's reign the Buddhist dharma had been heard in all corners of the Indian subcontinent, and, indeed, was starting to make its way even further afield. The very fact that most of the subcontinent had been welded into political unity under the Mauryan dynasty, founded by the Chandragupta (c. 321-298), no doubt facilitated such a rapid Buddhist expansion. Over and above this was the direct sympathy and support given by Ashoka, who after his particularly bloody campaign against the kingdom of Kalinga (Orissa) seems to have had a severe crisis of conscience that led him towards Buddhism. Thus it was that he came to refer to himself as a lay Buddhist (updsaka) at the rock inscriptions of Sahasram and Brahmagiri; while announcing his own reverence and faith in the 'Buddha, Dharma and Sangha' at the rock inscription of Calcutta-Bairat. I Under his aegis Buddhism thus spread throughout the Indian world.
In doing so, Buddhism came up against Hellenism. As a result of the meteoric career of Alexander the Great, Greek (including Macedonian) political power had been established across many lands, from the waters of the Aegean and the Nile to those of the Jaxartes and Indus. Following his premature death in 323 BC the Hellenic mantle in the east had been picked up by Seleucus, who from his capital Antioch held writ over Mesopotamia, the Iranian plateau, and the distant provinces of Sogdia and Bactria. However Alexander's conquests, and the Greek communities that he had left, in the Indus valley (hereafter referred to as NW India) were not to fall into Selucid hands. Seleucus himself c. 304 BC had in the course of his eastern campaigns encountered Chandragupta in NW India, but instead of