River Waveney between Norfolk and Suffolk was at that time a substantial feature. After the Romans conquered Britain in 43 AD, forts and roads were constructed around Norfolk as the Roman army became established. Major Roman roads in the county included the Peddars Way and Pye Road. After a minor rebellion by the Iceni in 47 AD king Prasutagus was allowed to rule independently as a client king. On his death in 60 AD Roman rule was imposed on the territory and his widow Boudica was not allowed to succeed him as Roman law only allowed male heirs to claim a client king's title. After Boudica was humiliated and her daughters raped she led a rebellion in which the towns of Colchester (Camulodunum), London (Londinium) and St. Albans (Verulamium) were sacked. Following the defeat of Boudicca the Romans restored order on the region by establishing an administrative centre at Venta Icenorum (the present Caistor St. Edmund), a small town built at Brampton and other settlements which were developed at river crossings or road junctions. The mostly rural population lived in scattered homesteads, villages or more affluent Roman villas. The level of the sea fell during Roman times and the swamps in the west of Norfolk slowly dried out. The land was then able to be converted into fertile farmland where sheep-rearing and salt production could be established. The Saxon Shore forts were built by the Romans in the 3rd century AD as a defence against overseas raiders. In Norfolk the ruins of the forts built at Burgh Castle (Roman Gariannonum), guarding the estuary across from the island of Flegg, still exist, but there is now little remaining of the forts at Brancaster (Branodunum) built on the north coast, and at Caister-on-Sea, on the east coast and near Burgh Castle. After the last of the armies of Rome had left in 410 AD most of the visible remains of Roman Britain slowly disappeared. Anglo-Saxon Norfolk Occupation and settlement The area experienced a depopulation during the fourth century, possibly due to raids from Saxons and Picts. Around 410 AD, Germanic-speaking settlers began to arrive from north-west Europe, thus placing the first phases of the Anglo-Saxon settlement of Norfolk before the supposed landing of Hengist and Horsa in Kent in 449. The migration here likely occurred on a very large scale; however, archaeologist Toby Martin has stressed that the settlers did not arrive