Mauryas
Chandragupta, the founder of Mauryan dynasty is said to have lived in Taxila when Alexander captured this city. According to tradition, he trained under Kautilya, who remained his chief adviser throughout his career. Supposedly using Gandhara and Vahika as his base, Chandragupta led a rebellion against the Magadha Empire and ascended the throne at Pataliputra in 321 BC. However, there are no contemporary Indian records of Chandragupta Maurya and almost all that is known is based on the diaries of Megasthenes, the ambassador of Seleucus at Pataliputra, as recorded by Arrian in his Indika. Gandhara was acquired from the Greeks by Chandragupta Maurya.
After a battle with Seleucus Nicator (Alexander's successor in Asia) in 305 BC, the Mauryan Emperor extended his domains up to and including Southern Afghanistan. With the completion of the Empire's Grand Trunk Road, the region prospered as a center of trade. Gandhara remained a part of the Mauryan Empire for about a century and a half.
Ashoka, the grandson of Chandragupta, was one of the greatest Indian rulers. Like his grandfather, Ashoka also started his career from Gandhara as a governor. Later he supposedly became a Buddhist and promoted this religion in his empire. He built many stupas in Gandhara. Mauryan control over northwestern frontier, including the Yonas, Kambojas, and the Gandharas is attested from the Rock Edicts left by Ashoka. According to one school of scholars, the Gandharas and Kambojas were cognate people. It is also contended that the Kurus, Kambojas, Gandharas and Bahlikas were cognate people and all had Iranian affinities, or that the Gandhara and Kamboja were nothing but two provinces of one empire and hence influencing each other's language. However, the local language of Gandhara is represented by Panini's conservative bhāṣā, which is entirely different from the Iranian (Late Avestan) language of the Kamboja that is indicated by Patanjali's quote of Kambojan śavati 'to go' (= Late Avestan šava(i)ti). Gandhara was often linked politically with the neighboring regions of Kashmir and Kamboja.
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