Wikipedia article: Achaemenid Empire

Question: who was the king who built a strong persian army and expanded the persian empire
Answer: The Achaemenid Empire ( / əˈkiːmənɪd / c. 550 -- 330 BC ), also called the First Persian Empire, was an empire based in Western Asia, founded by Cyrus the Great. Ranging at its greatest extent from the Balkans and Eastern Europe proper in the west to the Indus Valley in the east, it was larger than any previous empire in history, spanning 5.5 million square kilometers. Incorporating various peoples of different origins and faiths, it is notable for its successful model of a centralised, bureaucratic administration ( through satraps under the King of Kings ), for building infrastructure such as road systems and a postal system, the use of an official language across its territories, and the development of civil services and a large professional army. The empire 's successes inspired similar systems in later empires.

Question: is the achaemenid empire the same as the persian empire
Answer: The Achaemenid Empire ( / əˈkiːmənɪd /; c. 550 -- 330 BC ), also called the First Persian Empire, was an empire based in Western Asia, founded by Cyrus the Great. Ranging at its greatest extent from the Balkans and Eastern Europe proper in the west to the Indus Valley in the east, it was one of the largest empires in history, spanning 5.5 million square kilometers, and was larger than any previous empire in history. It is equally notable for its successful model of a centralised, bureaucratic administration ( through satraps under the King of Kings ), for building infrastructure such as road systems and a postal system, the use of an official language across its territories, and the development of civil services and a large professional army. The empire 's successes inspired similar systems in later empires. It is noted in Western history as the antagonist of the Greek city - states during the Greco - Persian Wars and for the emancipation of the Jewish exiles in Babylon.

Question: how did economic decline lead to the collapse of the achaemenid dynasty
Answer: Part of the cause of the Empire 's decline had been the heavy tax burden put upon the state, which eventually led to economic decline. An estimate of the tribute imposed on the subject nations was up to U.S. $180 M per year. This does not include the material goods and supplies that were supplied as taxes. After the high overhead of government -- the military, the bureaucracy, whatever the satraps could safely dip into the coffers for themselves -- this money went into the royal treasury. According to Diodorus, at Persepolis, Alexander III found some 180,000 Attic talents of silver besides the additional treasure the Macedonians were carrying that already had been seized in Damascus by Parmenion. This amounted to U.S. $2.7 B. On top of this, Darius III had taken 8,000 talents with him on his flight to the north. Alexander put this static hoard back into the economy, and upon his death some 130,000 talents had been spent on the building of cities, dockyards, temples, and the payment of the troops, besides the ordinary government expenses. Additionally, one of the satraps, Harpalus, had made off to Greece with some 6,000 talents, which Athens used to rebuild its economy after seizing it during the struggles with the Corinthian League. Due to the flood of money from Alexander 's hoard entering Greece, however, a disruption in the economy occurred, in agriculture, banking, rents, the great increase in mercenary soldiers that cash allowed the wealthy, and an increase in piracy.