Much of the northwestern Indian Subcontinent (present Afghanistan and most of Pakistan) was ruled by the Persian Achaemenid Empire from 520 BC during the reign of Darius I. The region of present-day Punjab, the Indus River from the borders of Gandhara down to the Arabian Sea, and some other parts of the Indus plain, became part of the empire.
Gandhara and Taxila in Punjab region was conquered by Achaemenid empire in 518 BC. During this time, Pushkarasakti was the king of Gandhara. The upper Indus region, comprising regions of Gandhara and Kamboja became the seventh satrapy and the lower and middle Indus comprising Sindh and Sauvira became the 20th satrapy of the Achaemenid Empire. This area was the most fertile and populous satrapy of the Achaemenid Empire.
During the Achaemenid rule, a system of centralized administration with a bureaucratic system was introduced in the region. Famous scholars such as Paṇini and Kautilya lived during this period. Indus Valley people were recruited to the Persian army and during the rule of Achaemenid emperor Xerxes, they took part in wars against the Greeks. Achaemenid rule lasted about 186 years. By about 380 BC, the Persian hold on the region was weakening, but the region continued to be a part of the Achaemenid Empire until it was conquered by Alexander.
