Gandharan Civilization was based in present day northern Pakistan and eastern Afghanistan, but its direct influence stretched from Central Asia to northwest India.
Gandhara was a part of Vedic, Persian, Greek, Bactrian, Scythian, Parthian, Kushan, Hephthalite, and other kingdoms/empires. It became a melting pot of Indo-Aryan, Iranian, Greek, and other cultures/peoples.
Buddhism was popular in Gandhara along with Hellenic beliefs, Zoroastrianism, Manichaeism, Mithraism, Shaivism, and Vedic beliefs.
Buddhism spread to east/northeast Asia from Gandhara via missionaries and traders using the Silk Road. Gandhara's location in the middle of the Silk Road also invited other cultures.
Gandhara was famous for its world class universities such as the one in Taxila where medicine, religion, sciences, literature, and arts were taught.
Gandhara's other contributions include the first linguistic system of grammar (Panini), the highly admired style of Greco-Buddhist arts, transmission of the concept of zero to the Arab world, and much more ...
Greek, Aramaic, Sanskrit, Old Persian, and Prakrits (local languages) such as Gandhari (written in Kharoshti script) were the spoken/written languages in Gandhara.
Despite becoming mostly Muslim, the Gandharan legacy lives on with the continuation of many aspects of culture, arts, traditions, etc. in present day Pakistan, Afghanistan, and beyond.
"My view is as vast as the sky, but my actions are finer than flour"
~ Padmasambhava ~