The Persian Empire, often called the Medo-Persian Empire, was the second great world empire represented in the dream of King Nebuchadnezzar (Daniel 2) of Babylon. It was the LARGEST empire in ancient history in terms of total land controlled.

Persia was the mountainous plateau east of the lower end of the Euphrates-Tigris Valley and its empire extending eastward into India and reached westward to Greece. Its capitals were Persepolis and Susa, with its kings sometimes residing at Babylon.

One of the first acts of the first Persian king, Cyrus, who was a "singularly noble and just monarch," was to authorize the return of the Jews to Jerusalem and to their own land (2Chronicles 36:22-23).