The Celtic Churches. A History, AD 200 to 1200, by John McNeill. University of Chicago Press ©1974
Celtics missionaries established Christianity in Europe by organizing “sending bases,” what we would call monasteries. Churches were also established, but Christianity expanded by monastery-missionary sending bases.
Columbanus establishes “sending bases” throughout western Europe and as far eastward as Moravia and Kiev. The impact of the missionary peregrine was strongly felt in Frankish Gaul through the work of Columbanus.
From the time a local ruler gave permission for Columbanus and his men to settle in Annegray, crowds of locals came, repenting of their sins, and asking to receive the remedies (medicamenta) of penance. Soon sheer numbers and the need of productive land required the creation of a new center, Luxeuil, eight miles away, where warm springs had attracted many in Roman times. A monastery was founded and rapidly became a community of thousands.
Columbanus and Gall made a journey of several years to establish more monastery sending bases. The great monastery at St. Gall with its magnificent library was one of these. King Agilulf of Lombardy permitted Columbanus to build a monastery at Bobbio on the Trebbia, a southern tributary of the Po.
In recent years scholars have become aware that Celtic monks played a pioneer role as missionaries in Slavic lands. Nearly a century before the Methodius and Cyril arrived in Moravia. There is evidence for the continuing presence of an Irish monastic community in Kiev from the late eleventh century to 1242.
Only a few have here been mentioned of an uncounted army of monks on pilgrimage for Christ from the late sixth to the early eighth century. That one small island should have contributed so rich a legacy to a populous continent remains one of the most arresting facts of European history. The Celtic mission planted a form of Christianity unimpeachable orthodox but singularly lacking in preoccupation with doctrinal issues. “The weight of the Irish influence on the continent,” wrote James Westfall Thompson, “is incalculable. It penetrated the still unchristianized regions of central Europe . . . For three hundreds years the light of Ireland flamed, shedding its rays upon Scotland, England and the Continent, until diminished in the darkness of the Norse invasions.”
Chapter 11 Irish Scholars in European Lands. The flow of Irish clerical migration across Europe continued through the eighth, ninth, and tenth centuries. But about the middle of the eighth century a change in motivation and approach is discernible. The early apostles of the movement with their kerygma of salvation give way in large degree to a new generation of professors whose qualifications and interests lay more largely in sacred and profane learning and the liberal arts than in going as exiles to the regions beyond.
Viking Invasions and the Destruction of the Monasteries.
The Viking raids on the monasteries of Iona and Lindisfarne are well-known. Not only the monasteries, but all along the Scottish coastlands and islands, uncounted hermitages and small communities were extinguished. The massacre of the monks of Eigg in 617 marks one of the early incursions of the sea-rovers in the Hebrides. Late in the seventh century they were molesting Irish monastic groups in the Shetlands. But it was a century later still that their raids began to reach the chief Christian centers. We read in the Anglo-Saxon Chronicle the ominous sentence for the year 793: “On the sixth of the Ides of June the ravaging of the heathen men lamentably destroyed God’s church at Lindisfarne.” Some of the Lindisfarne monks were stripped and tortured. In 801 the raiders came again, this time to destroy the buildings with fire. In 806, finding tenacious monks still on the site, the visitors slew as many as 80 of them. The abbey was rebuilt but in 867 was again burned by Danish pirates. In 870 the nuns of Coldingham in Berwickshire mutilated their own faces in order to escape outrage by the invaders; but they were mercilessly put to death with fire. While the nearby coasts were becoming the haunts of freely roving Vikings, on Lindisfarne the remaining monks maintained an existence until 875. In that year, expecting immediate attack they dug up and carried off St. Cuthbert’s and some of St. Aidan’s bones; then, with some lay fugitives, and driving their cattle before them, they crossed at low tide to the mainland and slipped away to safer ground.
Not less tragic was the fate of Iona. There the last remnant of the Roman-Celtic schism had ended only in 767. By 794 the long ships were wreaking havoc in the Hebrides, and in that year the buildings at Iona were looted. In 801 they were burned down, but the brethren struggled on. In 806, in a new onslaught, 68 of the monks were put to the sword, probably at Martyr’s Bay just south of the present village. Enfeebled and cut off from its dependent churches in Scotland, the remnant transferred its headquarters to Kells in Ireland in 814 (see chapter 8) and carried with them Columba’s relics in a gold and silver shrine.
Later Celtic Churches Incorporates in the Diocesan Model of Governance. “The abounding energy and apostolic impetuosity of an earlier day” gave way to the routine care of Christians of the next generations. In time little remained of the former Irish spontaneity and self-direction in continental lands. Succeeding generations accommodated themselves to the more efficient polity of what we normally think of as church. The abounding energy and apostolic impetuosity of an earlier day were no longer characteristic. In terms of great leadership and bold endeavor we enter on a descending slope.
McNeill, John Thomas. The Celtic Churches: A History A.D. 200 to 1200. University of Chicago Press, 1974.
 3 We always thank God when we pray for you, . . . because you learned the grace of God in truth from Epaphras, our fellow servant Colossians 1:3,7).
 John Thomas McNeill, The Celtic Churches: A History A.D. 200 to 1200 (University of Chicago Press, 1974). 16
 Ibid. 36
 Ibid. 35
 Ibid. 69
 Ibid. 37-8
 Ibid. 69-70
 Ibid. 70
 Ibid. 89
 Ibid. 118
 Ibid. 155
 Ibid. 155-6
 Ibid. 156
 Ibid. 157
 Ibid. 159
 Ibid. 163
 Ibid. 174
 Ibid. 221
 Ibid. 192
 Ibid. 175
 Ibid. 177
 Ibid. 206
 Ibid. 206
 Ibid. 206-7
 Ibid. 192