shah of Iran from 1694 to 1722, last independent ruler of the Ṣafavid dynasty, whose unfitness led to its disintegration.

Ḥusayn was reared in the harem and had no knowledge of state affairs. He depleted the treasury for personal expenses and allowed the mullahs (clergy) to control the government. Russia and Ottoman Turkey took advantage of Ḥusayn's weakness to seize border territory. Despite those losses, Ḥusayn ruled in relative peace for 20 years, while the nation slowly declined. Suddenly he was faced with a series of revolts by his tribal subjects, the most serious of which came from Maḥmūd, who had seized the throne of Afghanistan.

After making raids into Iran in 1720, the Afghans undertook a full-scale invasion in 1722. Maḥmūd marched on the capital at Eṣfahān and laid siege to the city. Seven months later Ḥusayn surrendered and abdicated, giving his crown to Maḥmūd.

Although two more members of the Ṣafavid royal house sat on the throne, they were but puppets, and Ḥusayn's reign accordingly marked the effective end of the dynasty.