The year 431 marks the date of the official introduction of Christianity to Ireland. In that year (according to Prosper of Aquitaine, Chronicle, s.a.) Pope Celestine I dispatched the newly ordained Palladius as "first bishop to the Irish believing in Christ" (primus episcopus ad Scottos in Christum credentes). Prosper appears to allude again to the mission of Palladius in his polemical tract Contra Collatorem (written in the later 430s in defense of Celestine against his detractors), when he refers to Celestine’s having made Britain (Romana insula, the Roman island) Catholic, while making Ireland (barbara insula, the barbarous island) Christian. Prosper was here referring to an earlier episode, in 429, when Celestine dispatched Germanus, bishop of Auxerre, to Britain in order to combat a recent recrudescence of the heresy known as Pelagianism. That mission (again according to Prosper) had been undertaken at the instigation of a deacon named Palladius, who is undoubtedly identical with the man of that name sent to Ireland in 431. It is generally assumed that the mission to Ireland in 431 followed on from the one to Britain in 429.
Native tradition, however, associates the beginnings of Irish Christianity with Patrick, not Palladius, who was subsequently written out of Irish history. Because Palladius disappears from the historical record in Ireland (and elsewhere) after 431, Irish historians were forced to fill the perceived void in the historical narrative by dating Patrick’s arrival immediately afterward, in 432. Patrick, a Briton by birth and upbringing, was captured at age sixteen by Irish pirates in a raid on his family’s estate (uillula), "along with many thousands of others" (as he says himself), and was brought to Ireland as a slave. His account of that episode, and of the events that unfolded because of it, has survived in his famous Con-fessio, which is a unique testimony to the experiences of a Roman citizen snatched from his home by alien marauders, and who lived to tell the tale. The Confessio and the only other writing of Patrick’s to survive, his letter addressed to the soldiers of Coroticus, offer unique insights into the everyday experiences of a man in the front line of missionary activity beyond the frontiers of the Roman Empire. Unfortunately, we do not know the dates of Patrick’s mission in Ireland. In fact, we have no dates at all for the saint, for the simple reason that he offers none, and no other reliable contemporary source exists that might fill that gap.
Modern scholars are unanimous that Patrick’s two surviving writings reveal an individual of genuine spiritual greatness. Historians have been troubled, however, by the fact that Patrick nowhere in his writings refers to Palladius or anyone else involved in missionary activity in Ireland, but constantly reiterates the claim that he has gone "where no man has gone before." It is not at all impossible, therefore, that Patrick came to Ireland before Palladius, rather than after him, perhaps in the late fourth century or in the generation before Palladius was dispatched by Pope Celestine to the "Irish believing in Christ." That would perhaps offer the most satisfactory explanation for Patrick’s otherwise inexplicable silence about the work of others before him on the Christian mission in Ireland. An earlier missionary period for Patrick would also account for the presence in Ireland of Christians before 431, those "Irish believing in Christ" to whom Palla-dius was sent as first bishop. Certain expressions in Patrick’s writings would seem to add weight to this surmise, since he appears to be writing at a time when the Roman presence is still all-pervasive in his native Britain. On the other hand, the more "traditional" dating of his career (arrival in 432, death in 461 or 493), runs up against the difficulty that the Roman legions had long since departed the "Saxon shore" and left Britain a prey to Anglo-Saxon invaders. Since Patrick makes no mention of these cataclysmic events, it seems reasonable to infer that his silence on the subject is due to the fact that he had left his native home long before the Anglo-Saxon occupation of Britain.
Palladius’s mission left nothing like the same impression on the Irish historical mind as Patrick’s did, and yet there are occasional traces of a transitional period during which Christianity was still finding its feet, not yet securely established as the "national" religion. In fact, that was probably not to be the case until the late sixth or early seventh century, at the earliest. The first phase of missionary activity is represented, for example, by a remarkable survival: a list of the days of the week in a mixture of Irish and Latin, a witness to the first faltering attempts by Irish Christians to adapt to the new concepts introduced by the Roman religion. This phase of conversion is evident also in the fact that the earliest Christian vocabulary used by Irish converts simply recycled the terminology of the older native beliefs. Thus the Irish terms for "God," "belief," "faith," "grace," and so on are all words used to express similar concepts in the pre-Christian religion. We know next to nothing about the progress of Christianity in Ireland in the fifth century, and Patrick himself refers only once (and that disparagingly) to native Irish practices of sun-worship "and other abominations," but he does not elaborate. In time, of course, the newer religion was to replace the earlier one entirely, but not before the latter had left an indelible mark on the Irish Christian mind. How much of the new Irish Christian religion was due to the activities of Palladius and his continental comrades, and how much to Patrick and the efforts of later British clergy, is difficult to judge. The evidence, such as it is, seems to indicate that the British influence in the longer term was the stronger of the two.
No document from the Palladian mission has survived, whereas Patrick’s two writings became the foundation for a body of legends that turned the humble Briton into an all-powerful, conquering Christian warrior who wiped out paganism and converted the Irish people single-handed. In the process of this reinvention, however, the true character of the man was sacrificed for the purpose of creating a mythological figure whose "heroic" deeds formed the basis for outlandish claims made by Irish churchmen in the centuries after him. When Patrick emerges into the light of history again in 632, in the famous Paschal letter of Cummian, he is there referred to as sanctus Patricias (the holy Patrick) papa noster (our father)—the earliest indication we have that Patrick enjoyed a special status in the Irish Church by that time.
