Constantinus I Magnus unifies the Roman Empire

The cities numbered in the map correspond to the mints of this period:
1 -  Londinium 2 -  Treveri 3 -  Lugdunum 4 -  Arelate
5 -  Aquileia 6 -  Ticinum 7 -  Roma 8 -  Ostia
9 -  Carthago 10 -  Siscia 11 -  Sirmium 12 -  Thessalonica
13 -  Heraclea 14 -  Cyzicus 15 -  Nicomedia 16 -  Antiochia
17 -  Alexandria            


A.D. 305-306
The second Tetrarchy: Constantius I and Severus II in the West, Galerius and Maximinus II in the East.


A.D. 306
From the death of his father, Constantinus governs in Hispania, Britannia and Gallia.


A.D. 312
Constantinus conquers Italia and Africa to the usurper Maxentius, becoming the only emperor of the West.


A.D. 314-317
The first war between Constantinus and Licinius finalizes with the treaty of peace of 317 in which Licinius loses his Western provinces (Illyria, Pannonia and Raetia).


A.D. 311-324
Territories controlled by Licinius from the death of Galerius (311), conquered by Constantinus in their second and definitive confrontation (324).


A.D. 311-324
Territories controlled by Maximinus II from the death of Galerius (311), occupied by Licinius in 313 and finally conquered by Constantinus in 324.


A.D. 324-337
In A.D. 324 Constantinus I Magnus becomes the only Roman Emperor. The Empire was unified and the collegiate system of government between four, established during the Tetrarchies, was completely overcome.

The empire remained unified just a short time. After the death of Constantine, his heirs would distribute the Empire (see map 2).