Daniel was one of God's prophets who found favor with several Babylonian and Persian kings. This allowed him to have influence over the decisions of these kings to do God's will. He was also saved by God when Persian king Darius was tricked by his officials into throwing him into the lion's den.
In 550, Cyrus the Great overthrew his grandfather and took control of Medea and the camps of Persia.
Cyrus the Great allows the Jews to return to their home, and orders the temple and city to be rebuilt. This is God fulfilling his promise to bring rebuild Judah
The people of Persia and it's conquered lands became restless and began to riot. King Darius took control, however, and put down the rebellion by showing his military strength.
Following an onslaught of victories against Persia at Grancius, Issus, and Guagemala, he attacked the capital, Persepolis and Persia surrendered. Persia's king was taken by own of his own subject and killed, so Bessus became king, but king of nothing, and he was soon put to death.
In the Battle of Opis, Cyrus the Great faced the Impenetrable walls of the city, but Cyrus had his men drain the euphrates and enter through the river gates. He overtook the city, and captured his largest opposing empire.
The famous battle between the 300 Spartans and the Persian Army. The Spartans, including their king, Leonidas, were slain, but held the Persians off long enough for Greece to amass and army.