The oldest country in the world is Iran (by date of the earliest known organized government). It was founded in 3200 BCE by the Achaemenid Empire (also called the First Persian Empire).
The Achaemenid Empire was a powerful empire that ruled over a large part of the world. The empire was founded by Cyrus the Great, the first emperor of Iran. The empire reached its height under the rule of Darius the Great. The Achaemenid Empire was eventually conquered by Alexander the Great.