Conquest of Babylon* (539 BC) 
The fall of Babylon is important in terms of the form of its conquest.
After the overthrow of the Median Empire and the establishment of the Achaemenid Empire by Cyrus, neighboring kingdoms including Lydia, Egypt, and Babylon united to become a common enemy against the Persians and took military action. Cyrus attacked Babylon after suppressing Lydia. Babylon was an ancient empire ruled by Nabonidus. By building several embankments to control the Euphrates, Cyrus made the river shallow and cut off Nabonidus's army from the city. On the other hand, Nabonidus was hated by the people of the city for his lack of love for the Babylonian god Marduk and for not holding the Akitu festival. The people of Babylon, who had heard of Cyrus's bravery, decided to open the city gates to him. The Persian troops were ordered not to do anything with the people of the city and their property, not to burn any house, and even a group was assigned to protect the Zagila idol. Cyrus had ordered that the Iranians should not do anything that was not befitting their freedom and nobility, and that the artists, scientists, and government officials should remain in their positions. Cyrus then issued his famous statement. He reassured the people that he did not intend to plunder, released the prisoners, and provided every possible consolation for the worshipers of Marduk. Cyrus even appointed Nebuchadnezzar, who had been captured in the war, to the governorship of Kerman (he remained in office until the end of his life) and spared his life. 
And so it was that Babylon lost its existence as an empire, without any conflict or bloodshed on the part of the Persians.