(Εἰρήνη), empress of Constantinople (A. D. 797-802), one of the most extraordinary women in Byzantine history, was born at Athens about A. D. 752.

She was so much distinguished by beauty and genius, that she attracted the attention of Leo, the son and afterwards successor of the emperor Constantine V. Copronymus, who married her in 769, the nuptials being celebrated with great splendour at Constantinople. She had been educated in the worship of images, and was compelled by her husband to adopt the purer form of religion which he professed. Leo was extremely kind towards her and her family both before and after his accession in 775; but having discovered that she still adored images, he banished her from his palace. Leo IV. died shortly afterwards (780), and Irene administered the government for her minor son, Constantine VI. The principal events of her regency are related in the life of Constantine VI.: we therefore confine ourselves to such occurrences as are in closer connection with her personal history. In 786 she assembled a council at Constantinople for the purpose of re-establishing the worship of images throughout the whole empire and the assembled bishops having been driven out by the riotous garrison of the capital, she found a pretext for removing the troops; and during their absence she assembled another council in 787, at Nicomedeia, where the adorers of images obtained a complete victory. The attempts of Constantine to emancipate himself from his mother's control are intimately connected with the religious troubles: they ended with the assassination of the young emperor by a band hired by Irene and her favourite, the general Stauracius. Irene succeeded her son on the throne (797), and had some difficulty in maintaining her independence against the influence of Stauracius and another favourite, Aetius, who, in their turn, were jealous of each other, and would have caused great dissensions at the court, and perhaps a civil war, but for the timely death of Stauracius (800). About this time Irene renewed the intercourse between the Byzantine court and that of Aix-la-Chapelle; and, if we can trust the Greek writers, she sent ambassadors to Charlemagne in order to negotiate a marriage between him and herself, and to unite the western and the eastern empires; and, according to the same sources, the plan first originated with the Frankish king. The whole scheme is said to have been rendered abortive by Aetius. The western writers do not even allude to this match, though Eginhard would certainly have mentioned it had Charlemagne actually entertained such designs. The scheme must therefore have been concocted at Constantinople, and kept there as a secret, which was only divulged after the death of the parties. From the accession of Charlemagne, the Greek emperors were no longer styled "father" and " lord" by the Frankish and German kings and emperors; but down to a late period the successors of Constantine refused the title of to the Roman emperors in Germany. Irene continued to govern the empire with great prudence and energy, but she never succeeded entirely in throwing oblivion over the horrible crime she had committed against her son; and she who trusted nobody was at last ensnared by a man who deserved her keenest suspicions, for the despicable vices of hypocrisy, avarice, and ingratitude. We speak of the great treasurer, Nicephorus, who suddenly kindled a rebellion, and was proclaimed emperor before the empress had recovered from her surprise and indignation. Irene proposed to share the throne with him; and Nicephorus having apparently acceded to her proposals, she received him with confidence in her palace, but was suddenly arrested and banished to the island of Lesbos (802). Deprived, through the base avarice of the usurper, of all means of subsistence, this haughty princess was compelled to gain her livelihood by spinning; and she died of grief in the following year, at the age of about fifty. Forgetful of her bloody crime, and only remembering her protection of images, the Greeks have placed her among their saints, and celebrate her memory on the 15th of August, the supposed day of her death.