After the conquest by Cæsar, the Romans retained possession of the island for four hundred years. During this time there were many rebellions in the various provinces, until at last the Britons submitted to their sway. Now another enemy advanced against this picturesque island. The Picts and Scots, hordes of lawless barbarians, who inhabited the mountains of Ireland and Scotland, made continual expeditions for plunder into the fair land of the Britons. At length one of the Roman emperors named Severus, visited the island of Britain, and endeavored to conquer the Picts and Scots. It was at this time that the famous Wall of Severus was built. The wall extended across the island, from the mouth of the Tyne on the German Ocean, to the Solway Frith, nearly seventy miles. This wall was a good defence against the barbarians, as long as Roman soldiers remained to guard it. But about two centuries after the time of Severus, the Roman soldiers were required by their own government at home, and the Britons were left to fight with the Picts and Scots alone. During this time another brave and warlike race had arisen. The Anglo-Saxons had now become powerful sea-rulers on the German Ocean and Baltic Sea. They delighted in storms and tempests, and cared not whether it was summer or winter when they sailed the seas, so brave and fearless were they. They would build small vessels of osiers, covering them with skins, and in these frail boats they courageously sailed amidst the rough winds and foaming surges of the German Ocean, in search of conquest and wild adventure. If they fought they conquered, and if they pursued their enemies they were sure to overtake them, and if they retreated they successfully made their escape. Neither winds, waves, nor enemies could quell this adventurous and brave race, which was fast rising into power and renown. They were clothed in loose and flowing garments, and wore their hair long, floating about their shoulders. They had much skill in fabricating arms of superior workmanship, which gave them a great advantage over their enemies. The landing of a few boat-loads of these determined and fearless Anglo-Saxons, on a small island near the mouth of the Thames, was an event which marks an important epoch in English history, as it was the real beginning of British greatness and power. The names of the commanders who headed the expedition of the Anglo-Saxons which first landed in Britain, were Hengist and Horsa. They were brothers. The island where they landed was called Thanet. The name of the king of Britain at this time was Vortigern. When the Anglo-Saxons arrived, his kingdom was distracted by the constant incursions of the Picts and Scots. In this danger, Vortigern appealed to the Anglo-Saxons for help. He offered to give them a large tract of territory in the part of the island where they had landed, if they would aid him in his contest with his enemies. Hengist and Horsa