Short answers, pulled from the story.
The name Cyrus appears as Kūruš in Old Persian inscriptions. Greek historians like Ctesias and Plutarch interpreted this name as meaning like the Sun, linking it to the Persian word for sun, khor.
Cyrus conquered Babylon in 539 BC following a campaign between 545 BC and 533 BC. The Nabonidus Chronicle notes that he brought peace to Babylonians and kept his army away from sacred sites while restoring temples neglected under previous rulers.
The Immortals unit consisted of 10,000 highly trained soldiers within the organized army created by Cyrus the Great. A general supervised military recruitment while state secretaries kept official records for both officials reporting directly to the central government and the satrap.
The Cyrus Cylinder was placed in the foundations of the Esagila temple dedicated to Marduk following the Persian conquest of Babylon in 539 BC. The United Nations declared it an ancient declaration of human rights in 1971, though historians note the modern concept did not exist then.
Cuneiform evidence proves he died around December 530 BC after campaigns against the Massagetae or Derbices infantry near the Syr Darya river. His remains were interred in Pasargadae within a limestone tomb built between 540 and 530 BC that became a UNESCO World Heritage Site in 2015.