The Nabonidus Chronicle is an ancient Babylonian text, part of a larger series of Babylonian Chronicles inscribed in cuneiform script on clay tablets. It deals primarily with the reign of Nabonidus, the last king of the Neo-Babylonian Empire, covers the conquest of Babylon by the Persian king Cyrus the Great, and ends with the start of the reign of Cyrus's son Cambyses II, spanning a period from 556 BC to some time after 539 BC. It provides a rare contemporary account of Cyrus's rise to power and is the main source of information on this period; Amélie Kuhrt describes it as "the most reliable and sober [ancient] account of the fall of Babylon."

Cyrus II of Persia, commonly known as Cyrus the Great, was the founder of the Achaemenid Persian Empire. Hailing from Persis, he brought the Achaemenid dynasty to power by defeating the Median Empire and embracing all of the previous civilized states of the ancient Near East, expanding vastly and eventually conquering most of West Asia and much of Central Asia to create what would soon become the largest polity in human history at the time. The Achaemenid Empire's largest territorial extent was achieved under Darius the Great, whose rule stretched from the Balkans and the rest of Southeast Europe in the west to the Indus Valley in the east.