calm, and levelheaded. At some point they may have merged with, or were perhaps synonymous to, the Saxons. Saxons had been raiding the eastern seaboard of Britain from here during the 3rd and 4th centuries (prompting the construction of maritime defences in eastern Britain called the Saxon Shore) and it is thought that following the collapse of the Roman defences on the Rhine in 407 pressure from population movements in the east forced the Saxons and their neighbouring tribes the Angles and the Jutes to migrate westwards by sea and invade the fertile lowland areas of Britain. The traditional date for this invasion is 449 and is known as the Adventus Saxonum. This began a vicious 400-year war of occupation and led to the creation of various Saxon kingdoms in England including that of the South Saxons (Sussex), the West Saxons (Wessex) and the East Saxons (Essex) alongside others established by the Angles and the Jutes and are the foundations of the modern English nation. After the fall of the Western Roman Empire in the 5th century the Old Saxons who remained in Germania were loosely associated with the Merovingian kingdom of Franks, but practically remained independent and maintained their old pagan religion (for more on this see: Germanic paganism). The Saxon pagan religion appears to have focused on the worship of the Irminsul or "great pillar"; a divine tree that connected Heaven and Earth and is thought to have existed at a site close to modern Obermarsberg. For the most part, the Saxon lands were a broad plain, save on the south, where they rose into hills and the low mountainous country of the Harz and Hesse. This low divide was all that separated the country of the Saxons from their ancient enemies and ultimate conquerors, the Franks. The lack of clear physical definition along this border, from time immemorial, had been the cause of incessant tribal conflict between them. Saxons as inhabitants of present-day Northern Germany are mentioned in 555, when Theudebald, the Frankish king, died and the Saxons used this opportunity for war. The Saxons were defeated by Chlothar I, Theudebald's successor. Some of their Frankish successors fought against the Saxons, while others were allied with them; Chlothar II won a decisive victory against the Saxons. In 690, two priests called Ewald the Black and Ewald the Fair set out from Northumbria to convert the Old Saxons