Forgotten Empire: The World of Ancient Persia, eds. John Curtis and Nigel Tallis. Berkeley Los Angeles: University of California Press, 2005.
The following summary comes from the material on page 12.
Because Classical texts have little to say about the Persians until the heroic origins of the empire’s founder Cyrus the Great (557-530 bc) who became king of Persia around 557 bc, the origins of the Persian people remains shrouded in mystery. Cyrus descended from a line of kings who ruled the country of Anshan east of the Persian Gulf. The kings of Anshan had close ties with the kings of Susa, another great city between Anshan and Babylonia (east of Babylonia and northwest of Anshan), and maintained a cultural and political relationship with the Medes whose heartland was caught between the Persians and Babylonia (northeast of Babylonia and northwest of the Persians).
Cyrus conquered The Median Empire (625-550 bc) around 550 bc before going on to subjugate the kingdom of Lydia and Asia Minor around 546 bc, and finally the Babylonian king Nabonidus around 539 bc. After his conquest of Babylonia, Cyrus authorized the Jewish Community to return to Jerusalem and rebuild the Temple of Yahweh and expanded his kingdom to the northeast as far as Bactria-Sogdiana, establishing forts along the left bank of the River Jaxartes which would be regarded as the northern border of the empire.
Cyrus disappeared during this campaign and was buried at Pasargadae in the heart of the Persian empire. By the time of his death, Cyrus had expanded a once small kingdom of Persia into a dominant empire that encompassed most of the Ancient Middle East, although Egypt was still left as the last large independent kingdom of the Middle East. Pharaonic Egypt was soon conquered by Cyrus’ son and successor—Cambyses (530-522 bc), although Cambyses died on his way back from his victory in Egypt.
In next post we will discuss the Empire’s first major setback.