Persian Empire timeline

3000 B.C.: Elamite Kingdom emerges
550 B.C.: Cyrus the Great founds Persian Empire
539 B.C.: Cyrus the Great conquers Babylon and releases the Jews from captivity
525 B.C.: Persia conquers Egypt
522 B.C.: Darius becomes king
490-449 B.C.: Persian Wars with Greece
334 B.C.: Alexander the Great conquers Persian Empire
323 B.C. Alexander dies in Babylon; his empire split and the Seleucid Empire forms
247 B.C.: The Parthians overthrow the Seleucids
224 A.D.: Sassanid Dynasty overthrows the Parthians
260: Shapur I captures Roman Emperor Valerian
642: Muslims conquer Persia

History Shorts: The Fall of Parthian Empire (224 A.D.)

Rome and Parthia fought a series on wars and skirmishes for control of the Middle East. The Parthian Empire fell around 224 A.D. It wasn't Rome, but internal and external factors broke the empire apart. Parthia's decline and fall helped open the door for eastern tribes to later invade the Roman Empire. The Sassanid Empire formed in its wake and existed until the Muslim conquest.

The following is from a documentary:

http://www.youtube.com/watch?v=IJ_1bshHnD8