'Empire' in the Bible

in those days when King Ahasuerus sat on his royal throne which was at the citadel in Susa [the capital of the Persian Empire],

Sharpen the arrows, take up the shields [and cover yourselves]!The Lord has stirred up the spirit of the kings of the Medes,Because His purpose concerning Babylon is to destroy it;For that is the vengeance of the Lord, vengeance [on Babylon] for [plundering and destroying] His temple.

The first (the Babylonian Empire under Nebuchadnezzar) was like a lion and had the wings of an eagle. I kept looking until its wings were plucked, and it was lifted up from the ground and made to stand on two feet like a man; a human mind was given to it.

And behold, another beast, a second one (the Medo-Persian Empire), was like a bear, and it was raised up on one side (domain), and three ribs were in its mouth between its teeth; and it was told, ‘Arise, devour much meat.’

After this I kept looking, and behold, another one (the Greek Empire of Alexander the Great), like a leopard, which had on its back four wings like those of a bird; the beast also had four heads (Alexander’s generals, his successors), and power to rule was given to it.

After this I kept looking in the night visions, and behold, [I saw] a fourth beast (the Roman Empire), terrible and extremely strong; and it had huge iron teeth. It devoured and crushed and trampled down what was left with its feet. It was different from all the beasts that came before it, and it had ten horns (ten kings).

Now in those days a decree went out from [the emperor] Caesar Augustus, that all the inhabited world (the Roman Empire) should be registered [in a census].