Arab-Islamic conquest of Persia
Who & why: Rashidun Caliphate armies defeat exhausted Sasanian forces at Qadisiyyah (636) and decisively at Nahavand (642), after decades of ruinous warfare between Persia and Byzantium had already weakened both empires. The last Sasanian king, Yazdegerd III, is killed near Merv in 651, ending over four centuries of Sasanian rule and closing the entire pre-Islamic Persian imperial arc.
What it represents: the closing point of this page's arc. Persia's continuing story — conversion to Islam over the following centuries, the Safavid dynasty's 1501 refounding of a distinctly Persian state, and the path to the modern Islamic Republic — is carried by this atlas's own Iran page.
Wikipedia: Arab-Muslim forces captured the derafsh after the Battle of al-Qadisiyyah (no year given). FOTW (pre-Islamic flags): the banner was lost to the Arabs at Qadisiyya, dated A.D. 637 in one footnote and about 636 from Preble's chronology; size about 22 by 15 feet; Preble says the captor received thirty thousand pieces of gold.
- Derafsh Kaviani — Wikipedia compiled
- Persia (Iran): Pre-Islamic flags — Flags of the World (CRW Flags) compiled
Not established: The era's flag content is the loss of the derafsh at Qadisiyya, which the two sources date to c. 636-637, outside the 633-651 span's endpoints; neither states the Sasanian fall in 651 as a flag event. Encyclopaedia Iranica was blocked (403) and not worked around.