The siege of Babylon by Cyrus the Great:  As the Persian Empire grew, its military strengthened. Cyrus developed an elite corps of mounted warriors who were skilled at shooting arrows on horse​​​​​back and deployed war chariots with blades attached to the wheels.  "His troops seem to have been highly motivated and well trained, and Cyrus himself appeared to have been an inspirational leader," John Lee, a history professor at the University of California, Santa Barbara says. "He seems to be able to move his armies more rapidly than enemies anticipated, even during winter.       After his army vanquished territories east of Persia, Cyrus set his sights on conquering the last remaining major power in the west of Asia-the Neo-Babylonian Empire.    In 539, Persian forces invaded the wealthy, fertile empire and routed the Babylonian army to sieze the strategic city of Opis on the Tigris River. A week later, the Persion army reached the walls of Babylon, the ancient world's largest city, and seized it without a fight.          According to the Cyrus Cilinder, a barrel-shaped piece of clay with Babylonian  cuneiform inscriptions that was unearthed in 1879, the Persian king triumphantly entered Babylon "in peace, amidst joy and jubilation."    Shortly after Babylon's fall, Cyrus liberated the Babylonian Jews who had been forced into captivity by Nebuchadnezzar II after the destruction of the Temple of Jerusalem 50 years earlier. Released from their Babylonian exile, many returned to their spiritual home in Jerusalem.  The book of Isaiah in the old testament extols Cyrus as being "anointed" by God to "subdue nations before him and to strip kings of their armour."  With the conquest of the Neo-Babylonian Empire, the Persian Empire sprawled from the Aegean Sea in the west to the Indus River in the east.  Cyrus had created one of the largest empires the ancient world had ever seen and was able to boast (per the Cyrus Cilinder): "I am Cyrus, king of the universe."            Little is known about the death of Cyrus, which occurred around 529 B.C. By some accounts, he died of a battle wound during a military campaign. His body was returned to Pasargadae, placed in a gold sarcophagus and laid to rest in an immense stone tomb oriented toward the rising sun.      Cyrus was succeeded by his son, Cambyses II, who continued to spread the boundaries of the empire by conquering another ancient civilization in Egypt. The Persian Empire remained prosperous and stable for two centuries until it fell in 330 B.C. to armies of Alexander the Great.                         Born around 600 B.C., the founder of the first Persian Empire (also known as the Achaemenid Empire) belonged to the semi-nomadic Pasargadae tribe, which raised sheep, goats and cattle in the southwest of present-day Iran. Cyrus was part of the Achaemenid royal family through either birth or marriage.