Cyrus the Great (558-530 BCE) built the first universal empire, stretching from Greece to the Indus River. This was the famous Achaemenid Empire of Persia. An inscription at Naqsh-i-Rustam, the tomb of his able successor Darius I (521-486 BCE), near Persepolis, records Gadara (Gandhara) along with Hindush (Hindus, Sindh) in the long list of satrapies of the Persian Empire.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/208/cultural-links-between-india--the-greco-roman-worl/.