The Bactrian and the Sogdian people are the principle ancestors of modern-day Tajiks [REF].
According to Richard Nelson Frye, a leading historian of Iranian and Central Asian history, the Persian migration to Central Asia may be considered the beginning of the modern Tajik nation, and ethnic Persians, along with some elements of East-Iranian Bactrians and Sogdians, as the main ancestors of modern Tajiks [REF].