Throughout time there have been a number of Persian Empires, but none of them can compare to the great Achaemenid Empire, which ruled between 550 to 330BC. The Achaemenid Empire is known as the largest empire in Ancient history which stretched out approximately 8 million km² at the height of its power. So how does an Empire so large and with such great power collapse? Was it struggle for power, which every new king had to suffer after the death of Darius the Great? Or was it because of corruption of the ministers and Satraps that made the empire decline. Maybe it could have been the invading Greek forces lead by Phillip the II of Macedon and his son Alexander the Great or are all these to blame?
The Achaemenid Empire was the largest Empire in Ancient history. It began as a small state located in modern day Iran. It is called the Achaemenid Dynasty is because of the Achaemenes who created the state. It is not until Cyrus the Great came into power in 559 BC did the expansion of Persia begin. He conquers the median empire that controlled Persia at that time and thereafter he and his successors go on to conquer most of the Middle East and Asia Minor, expanding out 8 million km². They even conquered part of Greece another formidable country at the time, but had to retreat after a loss at the Battle of Plataea. After this invasion of Greece is when we start to see a decline of power in the Empire until its eventual fall when King Darius the III died in 330BC.
The most obvious reason for why the Achaemenid Empire fell is the invasion of Greece by Alexander the Great During the reign and death of Artaxerxes the III, The Macedonian king, Phillip the II was forcibly uniting Greece. By 337 BC he had formed The League of Corinth. He was elected as the Leader of the army that would invade Persia but was assassinated as the invasion was commencing. His son Alexander the III (the Great) succeeds him as king of Macedonia and also takes