Iranians (ē rän′yans) or Persians, a branch of the Indo-European or Aryan family. In early times they peopled the entire country of Persia or Iran, and they are believed to form the connecting link between the Aryan races of Asia and of Europe. Ther first appearance in history is as the race of the Medes, 2400 B. C. The Iranians to-day are found west of the Indus River, and include the Afghans, Tajiks, Aimags and the Persian races, Kurds and Armenians. The oldest literature is contained in the sacred books of the Parsees or fire-worshipers, called the Zend-Avesta. Modern Persian is Iranic, with a large mixture of Arabic words.