Yazdegerd III ascends the throne as king (shah) of the Persian Empire. He becomes the last ruler of the Sasanian dynasty (modern Iran).

Yazdegerd III was the last Sasanian King of Kings from 632 to 651. His father was Shahriyar and his grandfather was Khosrow II.

Shāh is a royal title meaning "king" in the Persian language. Though chiefly associated with the monarchs of Iran, it was also used to refer to the leaders of numerous Persianate societies, such as the Ottoman Empire, the Khanate of Bukhara and the Emirate of Bukhara, the Mughal Empire, the Bengal Sultanate, and various Afghan dynasties, as well as among Gurkhas. With regard to Iranian history, in particular, each ruling monarch was not seen simply as the head of the concurrent dynasty and state, but as the successor to a long line of royalty beginning with the original Persian Empire of Cyrus the Great. To this end, he was more emphatically known as the Shāhanshāh, meaning "King of Kings" since the Achaemenid dynasty. A roughly equivalent title is Pādishāh, which was most widespread during the Muslim period in the Indian subcontinent.

The Sasanian Empire, officially Eranshahr, was an Iranian empire that was founded and ruled by the House of Sasan from 224 to 651. Enduring for over four centuries, the length of the Sasanian dynasty's reign over ancient Iran was second only to the directly preceding Arsacid dynasty of Parthia.

This is a family tree of the Sasanian emperors, their ancestors, and Sasanian princes/princesses.

Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the northeast, Afghanistan to the east, Pakistan to the southeast, and the Gulf of Oman and the Persian Gulf to the south. Iran ranks 17th globally in both geographic size and population and is the sixth-largest country in Asia. Iran is divided into five regions with 31 provinces. Tehran is the nation's capital, largest city, and financial center.