The classical meaning of peregrinus is “stranger;” in the Middle Ages the term was used to express the concept of “pilgrim.” While the stranger was by definition a person without legal standing, the pilgrim, in principle at least, was to enjoy a privileged status. In Irish society peregrinatio stood for an ascetic Christian ideal in the form of a self-imposed, life-long exile in pursuit of the personal salvation in a life lived according to Christ’s commands.

This peregrinatio comes into view first with Columbanus who left Ireland in 590 and lived for the rest of his life in Gaul and Italy. He died November 23, 615, in Bobbio (diocese of Piacenza). In his own writings the term peregrinus does occur without being further defined, but the concept of peregrinatio pro Christo can be deducted from the corpus of his writings as a whole, and in particular from his Instructiones.

However, the concept is clearly articulated in the Life of Columbanus, written by Jonas of Bobbio one generation after the saint’s death. This shows that the basis of Columbanus’s Christian concept was cherished in Bobbio beyond his death. According to Jonas, Columbanus was confronted with the concept of two degrees of peregrinatio, a lesser one practiced in the form of a self-chosen exile within Ireland and a stronger one by leaving Ireland. Jonas also reports that Columbanus successfully resisted plans to have him brought back to Ireland when he was forced to leave his monasteries in Burgundy circa 610.

Contrary to widespread views the Irish peregrinatio pro Christo was not connected with missionary intentions but remained the pursuit of personal salvation. This emerges clearly in Columbanus’s letter to Frankish bishops of circa 602 when he refused to attend a synod and instead expressed his wish for his community to be left alone to mourn their dead brethren in the wilderness (Ep. 2 p. 16: mihi liceat cum vestra pace et caritate in his silvis silere et vivere iuxta ossa nostrorum fratrum decem et septem defunctorum “that I may be allowed with your peace and charity to enjoy the silence of these woods and to live beside the bones of our seventeen dead brethren”).

In Lombard, Italy, Columbanus did preach Catholicism against the Arians, and he wrote a treatise on the subject (which has not survived). He did this at the request of the king, and it would appear that this was the price he had to pay for the permission to settle there.

It is most likely that the Irish concept of pererinatio pro Christo was developed under the inspiration of Irish secular law (not yet written) which knew two groups of foreigners, one within Ireland and one from overseas. The two classes of “foreigners” implied different status.

After Columbanus there were some more Irish Christians who pursued the peregrinatio pro Christo, such as Fursa or Cellach who settled in Peronne in Picardy. (It is not clear whether the Schottenkloster from the eleventh century onwards on the continent can be taken as expressions of this ideal.) Contrary to the widespread view which finds some apparent support in Adomnan’s Vita Columbae, Colum Cille, abbot of Iona (d. 597), was not a representative of this ideal because he visited Ireland after he had settled in Iona.

While the number of Irish peregrini pro Christo was small, their exemplary lifestyle proved to be inspiring on a large scale and was responsible for the enormous influence of Irish spirituality on early continental Christianity, including the system of penance. The question remains whether it seemed impossible for radical Irish Christians to live such a radical Christian life at home.