Battle of al-Qādisiyyah

At al-Qādisiyyah, on the desert edge southwest of the Euphrates, Saʿd ibn Abī Waqqāṣ's army met the Sasanian field force under Rustam. The battle ran four named days — the tradition remembers them by name, Armāth, Aghwāth, ʿAmās and the night of al-Qādisiyyah — before a sandstorm and Rustam's death broke the Persian centre.

The victory opened Ctesiphon, whose fabled carpet was cut and shared, and settled Iraq into the new order; Kūfah was founded as the army's city within a couple of years.

For all its fame, the battle's date is loosely carried: 14, 15 and 16 AH are all transmitted, and no month is agreed. The entry records the common reckoning at year precision — a reminder that fame and dating precision are different things.