AD 43 is a year in the early Roman imperial period, placed in the 1st century. In contemporary Roman usage it was identified by the names of that year's magistrates; official documents refer to it as the Year of the consulship of Claudius and Vitellius. In modern chronology it is labelled using the Anno Domini era.
Calendar and dating
The year was a common year beginning on Tuesday according to reconstructions of the Julian calendar. Ancient Romans did not use the AD numbering, so historians translate Roman consul names and regnal years into our calendar to place events in AD 43.
Major events
The most historically significant development dated to AD 43 is the start of the Roman conquest of Britain. Under the authority of Emperor Claudius, a military expedition led by the general Aulus Plautius crossed from Gaul and established a foothold on the island. Local rulers such as Togodumnus and his brother Caratacus resisted Roman advance, but key towns including Camulodunum (modern Colchester) fell and Roman administration began to take shape.
- Roman invasion and establishment of provincial control in southeastern Britain.
- Military operations and consolidation of Roman authority in newly occupied territories.
- Continued use of consular dating in Roman official records.
Significance and legacy
AD 43 marks the start of a long process that turned much of Britain into the Roman province of Britannia and left lasting cultural, linguistic and infrastructural influences on the island. The year is also an example of how Roman civic dating—naming years by consuls—interacts with later chronological systems historians use today.
For more detailed timelines and biographies related to this year, see entries on the year 43, the 1st century, and principal figures such as Claudius and the consul Vitellius.