The Romans in England:Carausius was the admiral of the Classis Britannica (the Roman Navy in Britain). He was so successful that he was accused of hoarding booty by the Roman Emperor Maximilian, and was forced to rebel to save his own life. He fled to Britain, which he seized along with northern Gaul, and began building a network of forts called the Saxon Shore (which acted as a defence both against Saxon raiders and attempts by the Empire to dislodge him).
Empire of Carausius 286 - 296 AD
Because he spent much of 287 waging war against the Germans, Maximilian did not attempt to repress Carausius until the next year when he began to build a fleet for use against the rebel. The emperor's fleet was ready in 289, but was destroyed by a storm before it could be used against the usurper.
However, by AD 293, the newly appointed Emperor, Constantius, was taking back his territories when Carausius was murdered by one on his own troops, Allectus. Allectus fell to Constantius three years later, who defeated him near Silchester, and prevented the retreating Franks from sacking London.