Bede's Ecclesiastical History of England, ed. by A.M. Sellar, [1907], at sacred-texts.com
In the year of our Lord 449, Marcian, the forty-sixth from Augustus, being made emperor with Valentinian, ruled the empire seven years. Then the nation of the Angles, or Saxons, being invited by the aforesaid king, arrived in Britain with three ships of war and had a place in which to settle assigned to them by the same king, in the eastern part of the island, on the pretext of fighting in defence of their country, whilst their real intentions were to conquer it. Accordingly they engaged with the enemy, who were come from the north to give battle, and the Saxons obtained the victory. When the news of their success and of the fertility of the country, and the cowardice of the Britons, reached their own home, a more considerable fleet was quickly sent over, bringing a greater number of men, and these, being added to the former army, made up an invincible force. The newcomers received of the Britons a place to inhabit among them, upon condition that they should wage war against their enemies for the peace and security of the country, whilst the Britons agreed to furnish them with pay. Those who came over were of the three most powerful nations of Germany—Saxons, Angles, and Jutes. From the Jutes are descended the people, of Kent, and of the Isle of Wight, including those in the province of the West-Saxons who are to this day called Jutes, seated opposite to the Isle of Wight. From the Saxons, that is, the country which is now called Old Saxony, came the East-Saxons, the South-Saxons, and the West Saxons. From the Angles, that is, the country which is called Angulus, and which is said, from that time, to have remained desert to this day, between the provinces of the Jutes and the Saxons, are descended the East-Angles, the Midland-Angles, the Mercians, all the race of the Northumbrians, that is, of those nations that dwell on the north side of the river Humber, and the other nations of the Angles. The first commanders are said to have been the two brothers Hengist and Horsa. Of these Horsa was afterwards slain in battle by the Britons, and a monument, bearing his name, is still in existence in the eastern parts of Kent. They were the sons of Victgilsus, whose father was Vitta, son of Vecta, son of Woden; from whose stock the royal race of many provinces trace their descent. In a short time, swarms of the aforesaid nations came over into the island, and the foreigners began to increase so much, that they became a source of terror to the natives themselves who had invited them. Then, having on a sudden entered into league with the Picts, whom they had by this time repelled by force of arms, they began to turn their weapons against their allies. At first, they obliged them to furnish a greater quantity of provisions; and, seeking an occasion of quarrel, protested, that unless more plentiful supplies were brought them, they would break the league, and ravage all the island; nor were they backward in putting their threats into execution. In short, the fire kindled by the hands of the pagans, proved God’s just vengeance for the crimes of the people; not unlike that which, being of old lighted by the Chaldeans, consumed the walls and all the buildings of Jerusalem. For here, too, through the agency of the pitiless conqueror, yet by the disposal of the just Judge, it ravaged all the neighbouring cities and country, spread the conflagration from the eastern to the western sea, without any opposition, and overran the whole face of the doomed island. Public as well as private buildings were overturned; the priests were everywhere slain before the altars; no respect was shown for office, the prelates with the people were destroyed with fire and sword; nor were there any left to bury those who had been thus cruelly slaughtered. Some of the miserable remnant, being taken in the mountains, were butchered in heaps. Others, spent with hunger, came forth and submitted themselves to the enemy, to undergo for the sake of food perpetual servitude, if they were not killed upon the spot. Some, with sorrowful hearts, fled beyond the seas. Others, remaining in their own country, led a miserable life of terror and anxiety of mind among the mountains, woods and crags.