Octavius was a legendary king of the Britons in
Geoffrey of MonmouthGeoffrey of Monmouth was a British clergyman and one of the major figures in the development of British history and the popularity of tales of King Arthur...
's
Historia regum BritanniaeThe Historia Regum Britanniae is a pseudohistorical account of British history, written c. 1136 by Geoffrey of Monmouth. It chronicles the lives of the kings of the Britons in a chronological narrative spanning a time of two thousand years, beginning with the Trojans founding the British nation...
, an early account of the rulers of Britain.
According to Geoffrey's story, Octavius was a half brother to
Constantine ICaesar Flavius Valerius Aurelius Constantinus Augustus , commonly known in English as Constantine I, Constantine the Great, or Saint Constantine , was Roman emperor from 306, and the sole holder of that office from 324 until his death in...
and ruled over Britain while Constantine was emperor in
RomeRome is the capital of Italy and the country's largest and most populated municipality , with over 2.7 million residents in , while the population of the urban area is estimated by Eurostat to be 3.46 million. The metropolitan area of Rome is estimated by OECD to have a population of 3.7 million...
. Constantine had been crowned king of the Britons upon his father's death in 306 at York. As Constantine became more powerful, he was forced to leave
BritainRoman Britain was those parts of the island of Great Britain controlled by the Roman Empire between AD 43 and about 410. The Romans referred to their province as Britannia...
in the hands of a proconsul while he ruled in Rome.
Octavius was a legendary king of the Britons in
Geoffrey of MonmouthGeoffrey of Monmouth was a British clergyman and one of the major figures in the development of British history and the popularity of tales of King Arthur...
's
Historia regum BritanniaeThe Historia Regum Britanniae is a pseudohistorical account of British history, written c. 1136 by Geoffrey of Monmouth. It chronicles the lives of the kings of the Britons in a chronological narrative spanning a time of two thousand years, beginning with the Trojans founding the British nation...
, an early account of the rulers of Britain.
According to Geoffrey's story, Octavius was a half brother to
Constantine ICaesar Flavius Valerius Aurelius Constantinus Augustus , commonly known in English as Constantine I, Constantine the Great, or Saint Constantine , was Roman emperor from 306, and the sole holder of that office from 324 until his death in...
and ruled over Britain while Constantine was emperor in
RomeRome is the capital of Italy and the country's largest and most populated municipality , with over 2.7 million residents in , while the population of the urban area is estimated by Eurostat to be 3.46 million. The metropolitan area of Rome is estimated by OECD to have a population of 3.7 million...
. Constantine had been crowned king of the Britons upon his father's death in 306 at York. As Constantine became more powerful, he was forced to leave
BritainRoman Britain was those parts of the island of Great Britain controlled by the Roman Empire between AD 43 and about 410. The Romans referred to their province as Britannia...
in the hands of a proconsul while he ruled in Rome. This prompted Octavius, then Duke of the Gewissei tribe of Celts, to begin a rebellion against Roman rule. Octavius murdered the proconsul and his aides then took the crown of Britain upon his own head.
This led to a response from Constantine who sent three legions to Britain under the command of his great-uncle,
TrahernTrahern Trahern Trahern ( is a legendary King of the Britons in Geoffrey of Monmouth's fictional Historia Regum Britanniae.According to Geoffrey, Trahern was king of the Britons and Roman senator...
, the brother of the late King
CoelKing Cole is a figure of British folklore.King Cole may also refer to:*"Old King Cole", nursery rhyme*King Cole , Major League Baseball pitcher*Nat King Cole , pianist and singer...
. He landed at Kaerperis and captured it forcing Octavius to conscript all the island into the army to combat the Roman legions. Octavius met Trahern in a field outside Winchester where they fought and Octavius won. Trahern fled to
AlbaAlba is the Scottish Gaelic name for Scotland. It is cognate to Alba in Irish and Nalbin in Manx, the other Goidelic Insular Celtic language, as well as similar words in the Brythonic Insular Celtic languages of Cornish and Welsh also meaning Scotland.Hence also the early classical name Albion...
ny and pillaged the land. That caused Octavius to react again, where he met Trahern in
WestmorlandWestmorland is an area of North West England and one of the 39 historic counties of England...
, but Octavius was defeated this time. Octavius fled Britain and Trahern took on the crown himself.
Octavius fled to
NorwayNorway , officially the Kingdom of Norway, is a country in Northern Europe occupying the western portion of the Scandinavian Peninsula, as well as Jan Mayen and the Arctic archipelago of Svalbard under the Spitsbergen Treaty...
where he sought help from King Gunbert. In Britain, supporters of Octavius managed to ambush Trahern and kill him near
London[]London is the capital of England and the United Kingdom. It has been a major settlement for two millennia, and the history of London goes back to its founding by the Romans, when it was named Londinium. London's core, the ancient City of London, the 'square mile', retains its medieval boundaries...
, allowing Octavius to return to Britain. Once arrived, he scattered the Roman forces and retook the throne of Britain, gaining an incredible amount of wealth and prestige. Following years of rule, Octavius decided to marry his only daughter off to the Roman emperor
Magnus MaximusMagnus Maximus , also known as Maximianus and Macsen Wledig in Welsh, was a Hispano-Roman usurper of the Western Roman Empire from 383 until his death, in 388, by order of Emperor Theodosius I.-Life:...
. After a brief struggle with his nephew,
Conan MeriadocConan Meriadoc was the semi-legendary 4th century leader of the earliest Brythonic settlement in Armorica and supposed founder of the house of Rohan....
, the kingship of Britain was given to Maximus, and Octavius abdicated.