But a severe retribution was exacted by Mohadi, the third caliph of the new dynasty, who seized, in his turn, the favorable opportunity, while a woman and a child, Irene and Constantine, were seated on the Byzantine throne.

An army of ninety-five thousand Persians and Arabs was sent from the Tigris to the Thracian Bosphorus, under the command of Harun, or Aaron, the second son of the commander of the faithful.

His encampment on the opposite heights of Chrysopolis, or Scutari, informed Irene, in her palace of Constantinople, of the loss of her troops and provinces.

With the consent or connivance of their sovereign, her ministers subscribed an ignominious peace; and the exchange of some royal gifts could not disguise the annual tribute of seventy thousand dinars of gold, which was imposed on the Roman empire.

The Saracens had too rashly advanced into the midst of a distant and hostile land: their retreat was solicited by the promise of faithful guides and plentiful markets; and not a Greek had courage to whisper, that their weary forces might be surrounded and destroyed in their necessary passage between a slippery mountain and the River Sangarius.