From an ancient Iranian tribe, Cyrus formed and then ruled the Persian Empire (from c. 559 - c. 529), extending it from Lydia through Babylonia. He is also familiar to those who know the Hebrew Bible. The name Cyrus comes from an ancient Persian version of Kourosh (Kūruš)*, translated into Greek and then into Latin. Kou'rosh is still a popular Iranian name.
Cyrus was the son of Cambyses I, king of Anshan, a Persian kingdom, in Susiana (Elam), and a Median princess. At the time, as Jona Lendering explains it, the Persians were vassals of the Medes. Cyrus revolted against his Median overlord, Astyages.
Cyrus conquered the Median Empire, becoming the first Persian king and founder of the Achmaenid dynasty by 546 B.C. That was also the year he conquered Lydia, taking it from the famously wealthy Croesus. Cyrus defeated the Babylonians in 539, and is called the liberator of the Babylonian Jews. A decade later, Tomyris, Queen of the Massagetae, led an attack that killed Cyrus. He was succeeded by his son Cambyses II, who expanded the Persian empire into Egypt, before dying after 7 years as king. [See Herodotus on Cambyses' conquest of Egypt.]
A fragmented inscription on a cylinder written in Akkadian cuneiform, describes some of the deeds of Cyrus. [See The Cyrus Cylinder.] It was discovered in 1879 during a British Museum excavation in the area. For what may be modern political reasons, it has been used to champion Cyrus as the creator of the first human rights document. There is a translation deemed by many to be a false one that would lead to such an interpretation. The following is not from that translation, but, instead, from one that uses more circumspect language. It does not, for instance, say Cyrus freed all the slaves.
Read the British Museum's translated Cyrus Cylinder.
* Quick note: Similarly Shapur is known as Sapor from Greco-Roman texts.