In the wake of the fall of Babylon, the Persians and Medes rose up in a great empire under Cyrus. His mighty rule stretched from the Indus to the mountainous reaches of central Asia through Babylonia and Arabia to Judea, where it met with the border of the Egyptian kingdom. Cyrus's son Cambyses II decided to add Egypt to the menagerie of the empire.
Despite his dreams, Cambyses conquered Egypt thoroughly in 525 BC. He made efforts to invade Kush to the south, but harsh deserts forced his armies to retreat. Later, he launched a failed expedition to punish the Oracle of Amin at the Siwa Oasis in which 50,000 men were buried in a freak sandstorm. His next military advance was planned against Carthage, but his Phoenician allies refused to fight against their brothers.
In 522 BC, word came to Cambyses that Bardiya had returned to Susa. The emperor formed up his army to destroy the usurper, but, according to his spear-carrier Darius, Cambyses was afraid. Victory seemed impossible against a man he had already killed, a crime he finally publicly confessed, though no one seemed to believe him. Cambyses stabbed himself in the thigh with his own sword, making to look like an accident, and died over a week later from gangrene. Darius gathered the army and returned to Susa himself.
Upon arrival in the capital, Darius met with the years-dead Bardiya. It seemed to be him, so much so that even his own wives in his harem said that it was he. The people loved him thanks to the negligent absence of Cambyses in Egypt and Bardiya's three-year celebration of tax remissions. However, as Bardiya had transferred the capital Media, the story began to unravel: Bardiya was actually Gaumata, a Medean magician from the east who had made himself to look like the dead prince. The Persian lord Otanes discovered the truth and gathered a group of his fellows, including Darius, to carry out an assassination.
They planned to catch the impostor by surprise in his castle, but Bardiya was tipped off by his network of spies. His guards caught the assassins, and they were hanged within hours. Bardiya went on to rule for decades more, turning eastward to expand the empire of the Medes deeper into the rich lands of India. In coming decades, there would be squabbles with the Greeks inhabiting Asia Minor, but the Bardiyan line would pacify the locals with shows of military strength, construction projects, and wealth through trade. Many suspected a Persian invasion across the Dardanelles, but the imperial attention went continually east.
In the fourth century BC, the Macedonians would descend upon Achean and conquer their fellow Greeks under Philip II. His son Alexander continued the unification of Greece by turning against the Persians. His invasion would cross like lightning through Asia Minor and into Judea, but the imperial counter-attack at the Siege of Babylon would kill the young conqueror with an army hardened by years of warfare conquering Indian kingdoms. With attention turned westward again, the Persians would reconquer Egypt and bring back their old allies in Phoenicia for a successful invasion of Greece. After putting the Greeks under control, they pressed westward in the Mediterranean, taking the defeated Carthage as a protectorate and conquering the upstart Latins in their village called Rome.
Eventually the Persian Empire would spread from what the Greeks called the Pillars of Hercules (Gibraltar) to the nestled southeastern edge of the Himalayas. Over the centuries, the empire would grow ungainly and weak, falling in the west to German barbarians and disintegrating into nation-states in a vast revolution. While the empire is a shadow of itself as Persia today, its foundations can be seen as Zoroastrianism stands as the principle philosophy of the world. That which is good works for the good in Ahura Mazda, and evil is evil, and to ask “What is good?” or “What is evil?” is a silly game attributed to Greeks.
In reality, Darius and his company successfully assassinated Bardiya. Darius would be named king of kings and the head of a new line of rulers. As one of his most famous actions, he attacked Greece to punish them for aiding Greek cities in uprising as he put down the rebellions among Bardiya-supporters. Persia yearly celebrates the death of Bardiya with the feast Magiophani (“The Killing of the Magician”) even twenty-five centuries later.