section_path: History/Classical period
section_name: Classical period
paragraph_text: Classical period
  
  The western regions of Pakistan became part of Achaemenid Empire around 517 BCE. In 326 BCE, Alexander the Great conquered the region by defeating various local rulers, most notably, the King Porus, at Jhelum. It was followed by the Maurya Empire, founded by Chandragupta Maurya and extended by Ashoka the Great, until 185 BCE. The Indo-Greek Kingdom founded by Demetrius of Bactria (180–165 BCE) included Gandhara and Punjab and reached its greatest extent under Menander (165–150 BCE), prospering the Greco-Buddhist culture in the region. Taxila had one of the earliest universities and centres of higher education in the world, which was established during the late Vedic period in the 6th century BCE. The ancient university was documented by the invading forces of Alexander the Great and was also recorded by Chinese pilgrims in the 4th or 5th century CE. At its zenith, the Rai dynasty (489–632 CE) ruled Sindh and the surrounding territories.