Persian, also known as Farsi (based on the ancient dialect spoken in the south-western part of the country, in the province of Fars, as it is still known today), belongs to the Indo-European family, Iranian group and is spoken by nearly 33 million people, mainly in Iran. It is one of the world's oldest languages, a standard and well-recognized tongue as early as the 6th century B.C. Old Persian was the language of the great Persian Empire which at one time extended from the Mediterranean to the Indus River in India.