The way in which the Roman world made its influence felt in Ireland should be compared with the ways in which it exerted influence over other adjacent countries. Let us take, for instance, Russia. Neither Russia nor Ireland ever passed for a moment under the rule of Caesar. Both states were neighbours of the Empire, and for the kings of Tara as for the princes of Kiev the Empire was the eminent fact in the political worlds with which they were acquainted. In both cases the intercourse of trade, varied by warfare, prepared the way for the ultimate reception of some of the ideas of the higher culture of Rome. But there was one essential difference, due to political geography. Ireland was of little consequence or account in the eyes of the Caesars of Old Rome, and it was only now and then, as in the days of Valentinian I., that they were called upon to give it a thought; whereas for the Caesars of the New Rome the existence of the Russian state, from its creation in the ninth century, was an important fact which entered permanently into the calculations of their foreign policy. The contrast between the presence of political relations in one case and their almost complete absence in the other is reflected in the contrast between the circumstances of the victory of Christianity in Russia and in Ireland. In Russia the faith of the Empire made, as it were, a solemn entry through the public portals of the State; in Ireland it entered privately through postern gates, and conquered from within. In Russia it was imposed upon his subjects by their prince Vladimir, who at the same time married a sister of the Roman Augusti; in Ireland it was only tolerated, when its success had begun, by the chief king, whose very name most probably never fell upon the ears of the Augustus at Ravenna. But in both cases the introduction of the religion was only a part, though the most important and effective part, of a wider influence diffused from the Empire. The great question with which Loigaire had to deal was the spread of Christianity in his dominion, a question which confronted barbarian kings just as it confronted Roman Emperors, and might be as embarrassing and critical for Loigaire in his small sphere as it had proved for the ecumenical statesmen Diocletian and Constantine. It is clear that in the days of Theodosius II. the moment had come when the High King of Ireland was constrained to adopt a definite attitude. If, as seems possible, it was in the south of Ireland, in the realms of Leinster and Munster, that this religion had hitherto made most progress, then, so long as it was tolerated by the sovereigns of those kingdoms, the High King might ignore it. But once it began to spread sensibly in his own immediate kingdom of Meath, as king of Meath he could not ignore what in other parts of Ireland the lord of all Ireland might pass over; the time had come when he had to decide whether he would oppose or recognise Christian communities and Christian priests.