Maxima Caesariensis was the name of one of the four provinces of later Roman Britain

Roman Britain

Roman Britain was the part of the island of Great Britain controlled by the Roman Empire from AD 43 until ca. AD 410.The Romans referred to the imperial province as Britannia, which eventually comprised all of the island of Great Britain south of the fluid frontier with Caledonia...

 (but is not named in the surviving copies of the Verona List

Verona List

The Laterculus Veronensis or Verona List is a list of Roman provinces from the times of the Roman emperors Diocletian and Constantine I. The list is transmitted only in a 7th-century manuscript, which is preserved in the Chapter House Library in Verona. The most recent critical edition is that of...

, dated 312

312

Year 312 was a leap year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Constantinus and Licinianus...

-314

314

Year 314 was a common year starting on Friday of the Julian calendar. At the time, it was known as the Year of the Consulship of Rufius and Annianus...

 AD). Its capital was Londinium

Londinium

The city of London was established by the Romans around AD 43. It served as a major imperial commercial centre until its abandonment during the 5th century.-Origins and language:...

 and probably encompassed what is now south east England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

. Originally, its governors were of equestrian rank but by the mid fourth century they had to be of consul

Consul

Consul was the highest elected office of the Roman Republic and an appointive office under the Empire. The title was also used in other city states and also revived in modern states, notably in the First French Republic...

ar rank. Maxima Caesariensis and its northern neighbour, Flavia Caesariensis

Flavia Caesariensis

Flavia Caesariensis was one of the provinces of Roman Britain.It was created in the early 4th century under the reforms of Diocletian and it has been suggested that its capital may have been at Lincoln...

, may have briefly comprised a single province which covered most of what is now eastern England. Eric Birley and others have suggested that the two provinces named Caesariensis were descended from a larger unit which received its unusual name due to Imperial favour. After London welcomed Constantius Chlorus

Constantius Chlorus

Constantius I , commonly known as Constantius Chlorus, was Roman Emperor from 293 to 306. He was the father of Constantine the Great and founder of the Constantinian dynasty. As Caesar he defeated the usurper Allectus in Britain and campaigned extensively along the Rhine frontier, defeating the...

 in 296

296

Year 296 was a leap year starting on Wednesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Valerius and Constantius...

 Birley argues that he may have granted it the additional title of 'Caesariensis'. Given the circumstances at the time Constantius may well have divided the military command of Britannia Superior

Britannia Superior

Britannia Superior was one of the provinces of Roman Britain created around 197 AD by Emperor Septimus Severus immediately after winning a civil war against Clodius Albinus, a war fought to determine who would be the next emperor. Albinus was the governor of Britannia during that civil war...

 in two with an eastern province named Britannia Caesariensis and a western one named Britannia Prima

Britannia Prima

Britannia Prima was one of the provinces of Roman Britain in existence by c. 312 AD. It was probably created as part of the administrative reforms of the Roman Emperor Diocletian after the defeat of the usurper Allectus by Constantius Chlorus in 296 AD. In the 3rd century, the Romans created...

. This division would have been later reorganised by splitting Britannia Caesariensis into north and south regions, named respectively Flavia after Constantius and Maxima after the western Augustus, Marcus Aurelius Valerius Maximianus. This would require the split to have taken place prior to Maximian's abdication in 305. As Constantius was elevated to the title of Augustus in the same year, London may also have adopted the title at the same time, as indeed it was later known. The short period of it holding the title Caesariensis may explain why there is little other evidence of that name. An alternative explanation, that the province was named after Galerius Maximianus

Galerius

Galerius , was Roman Emperor from 305 to 311. During his reign he campaigned, aided by Diocletian, against the Sassanid Empire, sacking their capital Ctesiphon in 299. He also campaigned across the Danube against the Carpi, defeating them in 297 and 300...

, emperor of the east, would have to account for an eastern emperor's being honoured, while the two Augusti of the Tetrachy were not.