The Nabonidus Chronicle (Babylonian Chronicle 7)

This tablet covers the reign of Nabonidus year by year, including the king’s long absence from Babylon. Its third column describes the Persian victory at Opis, the surrender of Sippar, the entry of Cyrus’s army into Babylon on the sixteenth day of the month and the arrival of Cyrus the Great himself on the third day of Arahsamna. The translation linked here does not print the name of the month in which the army entered. It falls after Ululu and before Arahsamna, which makes it Tašrîtu, the seventh month. The tablet is the main evidence for the date of Cyrus Takes Babylon.