The Angles began to advance from the coasts. In the year 586 they occupied all the country bounded on the north by the river Humber and the kingdom of Deira; on the west, by Wales, which alone remained in the hands of the Britons; on the south, by the Saxon kingdoms; and on the south-east, by the Angles of East Anglia. Mercia, as the new kingdom was called, comprised then on the south-east the northern part of the counties of Hertford and Bedford; on the east, all the counties of Northampton, Huntingdon, and Rutland; on the north, the counties of Lincoln, Nottingham, Derby, and Chester; on the west, Staffordshire, Shropshire, Worcestershire, and Herefordshire; in the centre of the island, Warwickshire and Leicestershire; on the south, Gloucestershire, Oxfordshire, and the county of Buckingham. In this kingdom, the most extensive of all, the British population had not been destroyed or driven back, as they had in the greater portion of other parts; they continued to inhabit their ancient country, mingled with and subject to the Angles. {29} Such was the division of Britain among the conquerors, and the constitution of the Saxon kingdoms. This is what is known as the Heptarchy, or Octarchy, according to whether we place the denomination before or after the union of the kingdoms of Deira and Bernicia in a single kingdom of Northumbria. Such was the new scene of the wars which were destined to break out again and deluge Britain, now become England, with blood. A more gentle influence was soon to exercise its effect upon the sanguinary passion of the barbarous races. The British Christians, though vanquished and driven back into the narrow territory of Cambria or Wales, do not seem to have attempted to convert their conquerors. For a moment they had themselves run the risk of falling into the heresies of Pelagius, an Irish monk who denied the doctrine of original sin; but the missionaries from Gaul, Saint Germain and Saint Loup, had succeeded in 429 and 446 in uprooting among them these disastrous tendencies. One day Saint Germain, who had been a soldier before being a bishop, found himself in the presence of a band of Picts and Saxons who were laying waste the coast. Putting himself at the head of his flock, he marched against the enemy amidst loud cries of "Alleluia!" These cries taken up by the neighboring echoes terrified the pirates, who fled; hence this peaceful victory became known by the name of "The Battle of the Alleluias."