Many Pashtuns believe that their ancestors were ancient Hebrews who arrived to what is now Afghanistan over 2,000 years ago and settled there. They were first mentioned by a Greek historian in 500 BC, then by Alexander the Great, and in the 3rd century they are called "Abgans" ("Afghans") by the Persian rulers. In the army of the Ghaznavids and Ghurids, thousands of Afghans were reported to be serving. They ruled Delhi Sultanate in the past and also Persia between 1725 to 1729 until they established the last Afghan empire that became what is now Afghanistan.