The Christian missionaries were still more active and successful: the Catholics asserted their universal reign; the sects whom they oppressed, successively retired beyond the limits of the Roman empire; the Marcionites and Manichæans dispersed their fantastic opinions and apocryphal gospels; the churches of Yemen, and the princes of Hira and Gassan, were instructed in a purer creed by the Jacobite and Nestorian bishops.

During the march, the Surenas, * or Persian general, and Malek Rodosaces, the renowned emir of the tribe of Gassan, incessantly hovered round the army; every straggler was intercepted; every detachment was attacked; and the valiant Hormisdas escaped with some difficulty from their hands.

In their way they overturned a detachment of Greeks, and when they joined at Yermuk the camp of their brethren, they found the pleasing intelligence, that Caled had already defeated and scattered the Christian Arabs of the tribe of Gassan.

From the provinces of Europe and Asia, fourscore thousand soldiers were transported by sea and land to Antioch and Cæsarea: the light troops of the army consisted of sixty thousand Christian Arabs of the tribe of Gassan.

That prince of the Saracens, who resided at Hira, had not been included in the general peace, and still waged an obscure war against his rival Arethas, the chief of the tribe of Gassan, and confederate of the empire. The subject of their dispute was an extensive sheep-walk in the desert to the south of Palmyra.

Being unfit for war himself, as he was above sixty years of age, he employed able generals, and within a few months of his accession struck such a series of blows that rebellion collapsed everywhere, and in a short time the whole Arab nation, except the tribe of Gassan, acknowledged themselves his subjects. Among the rivals against whom he measured himself, the most important was Moseilama.

The historians of the age of Justinian represent the state of the independent Arabs, who were divided by interest or affection in the long quarrel of the East: the tribe of Gassan was allowed to encamp on the Syrian territory: the princes of Hira were permitted to form a city about forty miles to the southward of the ruins of Babylon.

Determined now to spread his faith to the uttermost ends of the earth, he sent messengers to the rulers of all the civilized kingdoms that he knew. One went to Heraclius, Emperor of the Romans, who was in Syria at the time; one to the Roman Governor of Egypt, one to the King of Abyssinia and one to each of the provinces of Gassan and Yamam that were also under Roman control.