Emperor Domitian started his reign with the Roman campaign in Britain. Governor Gnaeus Julius Agricola continued in 82 with an attack against the Epidii. Followed with an invasion of the most northen part of the island, defeating a coalition of Caledonians and other tribes in the Battle of Mons Graupius in 84.
Emperor Domitian started his own military campaign in Germania, by defeating the Chatti in the north of the Agri Decumantes in 83.
Agricola was recalled as governor of Britain in 84 and the Romans retreated their army to a line between the Firth of Clyde and the Firth of Forth.
In 85, a second military invasion of the Chatti areas in the Agri Decumantes by Domitian resulted in the forcibly removal of the Chatti from Roman territory.
The Dacians under king Duras raided the Roman province of Moesia with a large force in 86. Domitian responded by sending Cornelius Fuscus with an army into Dacia, but he was defeated at a Battle of Tapae in 87, by the new Dacian king Diurpaneus, who received his new name Decebalus, the brave.
Decebalus was defeated at another Battle of Tapae in 88, by another Roman force. But, Domitian had to retreat from Dacia due to invasions of the neighbours of the Dacians, the Iazyges, Suebi, Sarmatians and Marcomanni in Roman Pannonia and the rebellion of governor Lucius Antonius Saturninus of Germania Superior. Dacia officially became a Roman vassal, but Rome paid the Dacians tribute to prevent future raids into Moesia and king Decebalus didn't keep his promises by building fortresses in his lands, which was forbidden according to the treaty. Domitian had to wage war with the Iazyges, Suebi and Quadi between 92 and 96 to stop their invasions into Roman territory.
Saturninus was defeated by general Trajan, who also did a punitive campaign against the Chatti, who had support the rebels from non-Roman Germania.
Domitian was killed in 96.