Ten months
On Mirza Khan’s advice, “to put to death the surviving males of the royal family … fifteen princes were accordingly murdered in one day.” When the king turned on the minister in his “drunken hours”, Mirza Khan “resolved to ensure his own safety by deposing the King”, lured him into the fort, and “thinking to appease the tumult by the death of Meeran Hoossein, commanded his head to be struck off, and placing it on a pole, planted it on one of the bastions of the citadel.”
The succession he made is one of the two the archive records as a usurpation; the succession that unmade him is an installation, because the man who chose the next king was a minister and not the crown.