from the attacks of the East-Romans. The Saracen and Bulgarian being driven away from the frontier, we are not surprised to hear that the empire flourished under Constantine. [Sidenote: Constantine’s home government.] He planted many colonies on the waste lands of the borders, settling the emigrant Christians of Armenia in Thrace, and many Slavonic and Bulgarian refugees in Bithynia. We are told that agriculture prospered in his time, so much that sixty measures of wheat sold for a gold solidus. He exterminated brigandage, and made the roads safe for merchants. He furnished Constantinople with a new water-supply by restoring the aqueduct of Valens, broken more than a hundred and fifty years before. When the capital had been devastated by a great plague in 746-7, he more than replaced the lost thousands of its population by new settlers from Hellas and the islands, for whom employment was found by the increasing commerce which followed the growth of internal prosperity. When he died in 775, aged fifty-seven, he left a full treasury, a loyal and devoted army, and a well-organised realm. Constantine was succeeded by his eldest son Leo IV., often called Leo the Chazar, because his mother Irene had been a Chazar princess. Leo had acted as his father’s colleague for many years, and carried on Constantine’s policy, though with a less harsh hand. [Sidenote: Reign of Leo IV., 775-80.] In the beginning of his reign he showed toleration to the Iconodules, but when they commenced to raise their heads again he resumed his father’s persecuting manner, flogging and banishing many prominent image-worshippers. He did not, however, object to monks, as Constantine had done, but allowed them to rebuild their convents, and even promoted some of them to bishoprics. It is probable that his resumption of persecution in 777 was connected with the discovery of a conspiracy against him in which his own brothers Nicephorus and Christophorus had leagued themselves with the discontented party. The treacherous Caesars were pardoned by their brother, and their associates suffered banishment and not death. Leo continued his father’s war with the Saracens. In 778 his armies invaded Commagene, defeated a great Saracen host in the open field, and brought back under their protection a great body of Syrian Christians, who were settled as colonists in Thrace. The caliph Mehdy replied in the next year by an invasion of the Anatolic theme: his army forced its way as far as Dorylaeum, but retired in disorder, and much harassed by the Romans, after failing to take that place.