Carausius Marcus Aurelius Mausaeus Valerius Carausius ( died 293 ) was a military commander of the Roman Empire in the 3rd century . He was a Menapian from Belgic Gaul , who usurped power in 286 , declaring himself emperor in Britain and northern Gaul . He did this only 13 years after the Gallic Empire of the Batavian Postumus was ended in 273 . He held power for seven years , before being assassinated by his finance minister Allectus ( see Carausian Revolt ) . History . Carausius was of humble origin , a Menapian who distinguished himself during Maximian ' s campaign against the Bagaudae rebels in northern Gaul in 286 . This success , and his former occupation as a pilot , led to his appointment to command the " Classis Britannica " , a fleet based in the English Channel , with the responsibility of eliminating Frankish and Saxon pirates who had been raiding the coasts of Armorica and Belgica . He was suspected of keeping captured treasure for himself , and of allowing pirates to carry out raids and enrich themselves before taking action against them , and Maximian ordered his execution . In late 286 or early 287 Carausius learned of this sentence and responded by declaring himself Emperor in Britain and northern Gaul . His forces comprised not only his fleet , augmented by new ships he had built , and the three legions stationed in Britain , but a legion he had seized in Gaul , a number of foreign auxiliary units , a levy of Gaulish merchant ships , and barbarian mercenaries attracted by the prospect of booty . British historian and archaeologist Sheppard Frere wonders how Carausius was able to win support from the army when his command had been sea - based , and speculates that he had perhaps been involved in an unrecorded victory in Britain , connected with Diocletian ' s assumption of the title " Britannicus Maximus " in 285 , and signs of destruction in Romano - British towns at this time . The campaign against the Bagaudae , however , was evidently land - based , and may have been responsible for Carausius ' s popularity with the army . Equally , if the accusations of larceny are true , he could perhaps have afforded to buy their loyalty . Maximian prepared an invasion of Britain in 288 or 289 to oust him , but it failed . A panegyric delivered to Constantius Chlorus attributes this failure to bad weather , but notes that Carausius claimed a military victory . Eutropius says that hostilities were in vain thanks to Carausius ' s military skill , and peace was agreed . Carausius began to entertain visions of legitimacy and official recognition . He minted his own coins and brought their value into line with Roman issues as well as acknowledging and honouring Maximian and then Diocletian . Coinage is the main source of information about the rogue emperor ; his issues were initially crude but soon became more elaborate and were issued from mints in Londinium , Rotomagnus and a third site , possibly Colonia Claudia Victricensis . Carausius appears to have appealed to native British dissatisfaction with Roman rule : he issued coins with legends such as " Restitutor Britanniae " ( Restorer of Britain ) and " Genius Britanniae " ( Spirit of Britain ) . He also used coins for more sophisticated propaganda . He issued the first proper silver coins that had appeared in the Roman Empire for generations , knowing that good quality bullion coinage would enhance his legitimacy and make him look more successful than Diocletian and Maximian . Some of these silver coins bear the legend " Expectate veni " , ' Come long - awaited one ' , recognised to allude to a line in the Aeneid by the Augustan poet Virgil , written more than 300 years previously . He was trying to suggest that not only was he , Carausius , a kind of messianic new ruler , but was also showing his association with Roman culture rather than any kind of remote provincial culture . Some of the silver coins bear the legend RSR in the exergue ( an area on a coin below the legend ) . This was considered a mystery for some time . Two Carausian medallions , now in the British Museum have also been found . One has RSR in the exergue ; the other has INPCDA . Since 1998 these letters have been recognised as representing the sixth and seventh lines of the Fourth Eclogue of Virgil , which reads " Redeunt Saturnia Regna , Iam Nova Progenies Caelo Demittitur Alto " , meaning ' The Golden Ages are back , now a new generation is let down from Heaven above ' . This poem was as famous in the Roman world as Shakespeare ' s works are today , so any educated reader would certainly have realized what the initials stood for ( it was commonplace in antiquity to reduce slogans and phrases to abbreviations ) . No other Roman emperor in history ever made such an explicit reference to famous Roman literature . It is quite extraordinary that in a remote province like Britain a rebel emperor should utilise such a method to appeal to his public . He was claiming to represent a revival of traditional Roman virtues and the great traditions of the Empire as established by Augustus in the last decades of the first century BC , not in Rome but in Britain . A milestone from Carlisle with his name on it suggests that the whole of Roman Britain was in Carausius ' grasp . This situation continued until 293 , when Constantius Chlorus , now the western Caesar , marched into Gaul and reclaimed it for the empire . He isolated Carausius by besieging the port of Bononia , and invading Batavia in the Rhine delta , securing his rear against Carausius ' s Frankish allies . He could not yet mount an invasion of Britain until a suitable fleet could be built . Nevertheless , Carausius ' s grip on power was fatally undermined . Allectus , whom he had put in charge of his treasury , assassinated him and assumed power himself . His reign would last only three years , after which he was defeated and killed by Constantius ' s subordinate Julius Asclepiodotus . In April 2010 a large hoard of coins was unearthed near Frome , Somerset , United Kingdom , which includes the largest group of coins issued during Carausius ' reign ever found ; 760 coins from his reign were found in a group of 52 , 500 Roman coins that also included 5 rare silver denarii . The find was equivalent to four years pay for a Roman legionary and dates from later than his reign , however , as it includes coins struck at a later date . Legend . In Geoffrey of Monmouth ' s legendary " History of the Kings of Britain " ( 1136 ) Carausius is a Briton of humble birth , who by his courage persuades the Roman Senate to give him command of a fleet to defend Britain from barbarian attack . Once given the fleet , however , he sails around Britain stirring up unrest , and raises an army against Bassanius , the historical Caracalla , here a king of Britain . Carausius defeats Bassanius by persuading his Pict ish allies to desert him in exchange for grants of land in Scotland , and sets himself up as king . Hearing of Carausius ' s treachery , the Romans send Allectus to Britain with three legions . Allectus defeats and kills Carausius and sets himself up as king in his place .