There was no lack of petty violations of the treaty by one side or the other; the Arabs on both sides alone took good care of that. At all events Chosroes was this time eager for war, and he therefore started early in the year 540 to invade Syria as Sapor I had done. He passed by the strongly fortified cities which bought him off by the payment of large sums, those which offered resistance he took. This fate fell heaviest upon Antiochia, the metropolis. The army left it laden with booty, which included many works of art. He burned the city and carried off its inhabitants. After advancing to the shores of the “Roman” Sea, he continued his victorious progress through northern Syria and Mesopotamia, from west to east. The fortress of Dara, which had always been an eyesore to the Persians because it had been built in contravention of the treaty, was obliged to purchase safety at a price. None went free without payment except the inhabitants of Carrhæ, who, being still heathen, might be supposed to entertain sympathy for the non-Christian empire. At the end of the summer he reached Ctesiphon again, without having encountered any open resistance in the field. In the second year of the war Chosroes marched to Lazistan at the request of the inhabitants, penetrated to the Black Sea, and there took the strong fortress of Petra. The struggle was continued for several years in Mesopotamia with variable fortune. In 546 a truce was concluded for five years on payment of a large sum of money by the Romans. But Lazistan territory was excluded from the operation of the truce, both then and in 553, when the armistice was prolonged for a further period of five years. The Arabs of the two empires also continued to fight with one another. Not until 556 was the armistice extended to Lazistan, the Roman arms having made some progress in the meantime, and about Christmas, 562, a peace was concluded for fifty years. The Romans again pledged themselves to pay a considerable sum every year, the Persians resigned their claims to Lazistan, but the question of who should possess the neighbouring province of Suania remained undecided. Our information concerning the articles of this peace happens to be exceptionally detailed; one important provision is that, though stipulating for full religious liberty for Persian Christians, the Romans recognise that they are prohibited from proselytising among Zoroastrians; and consequently that severe punishment inflicted for the infringement of this prohibition does not constitute a violation of the articles of peace.