Bernicia seized on the fall of Eadwine to recall the line of Æthelfrith to its throne; and after a year of anarchy his second son, Oswald, became its king. The Welsh had remained encamped in the heart of the north, and Oswald's first fight was with Cadwallon. A small Northumbrian force gathered in 635 near the Roman Wall, and pledged itself at the new King's bidding to become Christian if it conquered in the fight. Cadwallon fell fighting on the "Heaven's Field," as after times called the field of battle; the submission of Deira to the conqueror restored the kingdom of Northumbria; and for seven years the power of Oswald equalled that of Eadwine. It was not the Church of Paulinus which nerved Oswald to this struggle for the Cross, or which carried out in Bernicia the work of conversion which his victory began. Paulinus fled from Northumbria at Eadwine's fall; and the Roman Church, though established in Kent, did little in contending elsewhere against the heathen reaction. Its place in the conversion of northern England was taken by missionaries from Ireland. To understand the true meaning of this change we must remember how greatly the Christian Church in the west had been affected by the German invasion. Before the landing of the English in Britain the Christian Church stretched in an unbroken line across Western Europe to the furthest coasts of Ireland. The conquest of Britain by the pagan English thrust a wedge of heathendom into the heart of this great communion and broke it into two unequal parts. On one side lay Italy, Spain, and Gaul, whose churches owned obedience to and remained in direct contact with the See of Rome, on the other, practically cut off from the general body of Christendom, lay the Church of Ireland. But the condition of the two portions of Western Christendom was very different. While the vigour of Christianity in Italy and Gaul and Spain was exhausted in a bare struggle for life, Ireland, which remained unscourged by invaders, drew from its conversion an energy such as it has never known since. Christianity was received there with a burst of popular enthusiasm, and letters and arts sprang up rapidly in its train. The science and Biblical knowledge which fled from the Continent took refuge in its schools. The new Christian life soon beat too strongly to brook confinement within the bounds of Ireland itself. Patrick, the first missionary of the island, had not been half a century dead when Irish Christianity flung itself with a fiery zeal into battle with the mass of heathenism which was rolling in upon the Christian world. Irish missionaries laboured among the Picts of the Highlands and among the Frisians of the northern seas. An Irish missionary, Columban, founded monasteries in Burgundy and the Apennines. The canton of St. Gall still commemorates in its name another Irish missionary before whom the spirits of flood and fell fled wailing over the waters of the Lake of Constance. For a time it seemed as if the course of the world's history was to be changed, as if the older Celtic race that Roman and German had swept before them had turned to the moral conquest of their conquerors, as if Celtic and not Latin Christianity was to mould the destinies of the Churches of the West.