In Daniel chapter 2, King Nebuchadnezzar has a dream in which Daniel interprets. The dream and its interpretation applied toward the kingdoms that would rule the earth until Christ returns and sets up the final kingdom in which Christ will rule and reign on earth for a thousand years. The prophecy was given in or around the time of Babylon's rule in about 600 BC.
A more in depth summary of this chapter is as follows:
The king has a disturbing dream and asks his wise men to interpret it, but refuses to divulge its content. When they protest he sentences all of them, including Daniel and his friends, to death. Daniel intervenes and asks for a temporary stay of execution so that he can petition his God for a solution. He receives an explanatory vision in the night, and then relays the content and meaning of the king's dream the following day. Nebuchadnezzar has dreamed of an enormous idol made of four metals, with feet of mixed iron and clay. The image is completely destroyed by a rock that turns into a huge mountain, filling the whole earth. The idol's composition of metals is interpreted as a series of successive kingdoms, starting with Nebuchadnezzar. Finally all of these dominions are crushed by God's kingdom, a kingdom that will "endure forever".History itself has interpreted the meaning of the dream. Daniel revealed that the head of gold represented the Babylonian empire (Daniel 2:37). Babylon crumbled, being over rode by the Medes and Persians. The Persians were then conquered under the leadership of Alexander the Great in 334BC and the Roman Empire then eventually came to rule the world for over a half century. The Roman empire was divided between the east and west with Rome, Italy and Constantinople, Turkey (Istanbul today) being he eastern leg; thus fulfilling the prophecy.
The Kingdoms are thus as follows:
1. Babylonian Empire---600 BC
2. Medio-Persian Empire---450 BC
3. Grecian Empire---300 BC
4. Roman Empire---150 BC to about 476AD
Doubting that Daniel could have predicted these events so long in advance? Many were skeptical until the Dead Sea Scrolls were found the caves in Qumran in the 1950's. These scrolls mentioned Daniel by name and provided authenticity to prophecies.
Here are a couple critiques on when Daniel was written:
Dead Sea Scrolls. When was Daniel written? The Dead Sea Scrolls provide the first proof that the book of Daniel existed before 165 BC, since Daniel was found among the manuscripts at Qumran. This early date is the result of radiocarbon dating of the Dead Sea manuscripts of Daniel. They imply that earlier copies of the book with older dates already existed.
Ezekiel's Reference. Most critics widely accept the book of Ezekiel as being written between 586 BC and 538 BC. What is fascinating is that the author, Ezekiel, refers to Daniel in Ezekiel 14:14, 20. This implies that Daniel was alive during his time. Daniel claims to be the author (Daniel 12:4) of the book which bears his name and to have lived during the life of Nebuchadnezzar (Daniel 1-2) and Darius (Dan. 9:1). This implies that Daniel was a contemporary of Ezekiel and lived to see the fall of Babylon (Dan. 5:30-31).
Another good summary of Daniel 2 can be found here.