The questions of when and why did the ancient Roman Empire leave Britain has been discussed among historians for many years. Some historians make the case that it was Rome who abandoned Britain while others suggest it was Britain through various uprisings that abandoned Rome. Looking at history, it appears both arguments have their merits.
(“Hadrian’s Wall view near Greenhead” by Mark Burnett. Licensed under CC BY-SA 3.0 via Wikimedia Commons)
Most historians like to point to 409 or 410 CE as the two most likely dates when the Roman military had finally pulled out of Britain permanently. Reasons for Roman abandonment of Britain included the problem of barbarian attacks from various tribal groups at home as well as in Britain. This coupled with various uprisings against Roman leadership from the Britons put a great strain on the Roman military. Uprisings in Britain were not just done by the native Britons themselves. Several times Roman leaders whose power was based in Britain tried to seize imperial authority. The most well-known case involved Roman-Britain general Magnus Maximus, who crossed the Gaul and killed Western Roman Emperor Gratian, thereby becoming ruler of Gaul and Britain. Eventually Maximus was executed by Theodosius in 388. Constant usurpation of Roman emperors led to a lack of coherent policy throughout the Roman Empire, inevitably affecting its rule over Britain and the rest of its vast empire.
In the year 409 CE, the Roman army had proved itself to be very unpopular in Britain causing the Britons to revolt even more. This along with an expulsion of Roman-Britain magistrates could have been the deciding point for Emperor Constantine III to finally call an end to military occupation of Britain. In 410 CE, Emperor Honorius told the Britons after a request for military assistance against invaders such as the Saxons, that Rome was officially done assisting Britain militarily and that they were to be left to defend themselves.
Coin of Constantine III
(“Siliqua Constantine III-RIC 1355” by Classical Numismatic Group, Inc. http://www.cngcoins.com. Licensed under CC BY-SA 3.0 via Wikimedia Commons)
“Hadrian’s Wall view near Greenhead” by Mark Burnett. Licensed under CC BY-SA 3.0 via Wikimedia Commons.
“The Britons.” Hadrian’s Wall.Web. 11 Apr. 2015. <http://explore-hadrians-wall.com/history/history_9.php#>.
“The End of Roman Britain.” Google Books. Web. 11 Apr. 2015.
“Roman Britain Timeline.” Roman Britain Timeline. Web. 11 Apr. 2015. <http://www.historyonthenet.com/chronology/timelineroman.htm>.
“Siliqua Constantine III-RIC 1355” by Classical Numismatic Group, Inc. http://www.cngcoins.com. Licensed under CC BY-SA 3.0 via Wikimedia Commons.