Constantius Chlorus assembles two invasion fleets with the intent of crossing the English Channel. The first is under the command of Asclepiodotus, Constantius' long serving Praetorian Prefect. He sails from the mouth of the Seine, and lands near the Isle of Wight, where his forces defeat the usurper Allectus in Hampshire. Constantius leaves with his fleet Boulogne and occupies London, saving the city from an attack by Frankish mercenaries who are roaming the province.
Maximian, emperor (Augustus) of the Roman Empire, mobilises an army, consisting of Praetorian cohorts, Aquileian, Egyptian, and Danubian legionaries, marching through Spain. He crosses the Strait of Gibraltar into Mauretania (modern Morocco) to protect the area against Frankish pirates.
Constantius Chlorus reconquers Britain; he rebuilds the cities Eboracum (York), Londinium (London), and Verulamium (St Albans).
Emperor Diocletian dispatches his son-in-law Galerius with a large army to Armenia. He invades Mesopotamia, but suffers a complete defeat outside Ctesiphon against the Persian king Narseh, and is forced to retreat. Galerius crosses the Euphrates into Syria to join Diocletian at Antioch.
April 22 – Pope Caius dies at Rome after a 13-year reign and is succeeded by Pope Marcellinus as the 29th pope.
April 22 – Pope Caius
Allectus, Roman usurper
Year 296 (CCXCVI) was a leap year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Valerius and Constantius (or, less frequently, year 1049 Ab urbe condita). The denomination 296 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.