Persia (also known as Iran) is home to one of the world's oldest civilizations, beginning with the formation of the Elamite kingdoms in the fourth millennium BCE. It was first unified by the Iranian Medes in the seventh century BCE, reaching its greatest territorial size in the sixth century BCE, when Cyrus the Great founded the Achaemenid Empire, which stretched from Eastern Europe to the Indus Valley, becoming one of the largest empires in history.
Persian (also known as Parsi) is one of the Western Iranian languages within the Indo-Iranian branch of the Indo-European language family. It is primarily spoken in Iran, Afghanistan (officially known as Dari since 1958), and Tajikistan (officially known as Tajiki since the Soviet era), Uzbekistan and some other regions which historically were Persianate societies and considered part of Greater Iran.
Persians are an Iranian ethnic group that make up over half the population of Iran. They share a common cultural system and are native speakers of the Persian language, as well as closely related languages. The ancient Persians were a nomadic branch of the ancient Iranian population that entered the territory of modern-day Iran by the early 10th century BC. Together with their compatriot allies, they established and ruled some of the world's most powerful empires, well-recognized for their massive cultural, political, and social influence covering much of the territory and population of the ancient world. Throughout history, the Persians have contributed greatly to various forms of art and science, and own one of the world's most prominent literatures.