On 19 August 797 Constantine was captured, blinded, and imprisoned by the supporters of his mother, who had organized a conspiracy, leaving Irene to be crowned as first Empress regnant of Constantinople. It is unknown when exactly Constantine died; it was certainly before 805, though he may have died of his wounds shortly after being blinded. 

A member of the politically prominent Sarantapechos family, she was selected as Leo IV's bride for unknown reasons in 768. Even though her husband was an iconoclast, she harbored iconophile sympathies. During her rule as regent, she called the Second Council of Nicaea in 787, which condemned iconoclasm as heretical and brought an end to the first iconoclast period (730–787).