There is good reason to regard
Julius Caesar as the first
emperor, and he was so called throughout the
Middle Ages, but the convention these days is that we start with
Augustus as the first. With his reign the empire became continuous. See
Princeps by
Gone Jackal (and to a lesser extent my
Roman Empire) for a more detailed discussion of the comparative powers and titles of Caesar and Augustus.
The names Caesar and Augustus, and the military title Imperator, all continued as part of the regnal titles of the emperors. (In the later period of the Tetrarchy the Caesar was deputy emperor to the Augustus.) Their full names and styles were often very complex; the names given here are the more familiar ones.
Where multiple emperors are given at the same time, there are three possible causes: (i) they were killed or overthrown in quick succession (e.g. the year 69); (ii) the emperor shared power with his son or other intended successor; or (iii) they were rivals appointed by troops in different parts of the empire. I have made some explanatory notes where I can work out what happened.
- Augustus 27 BCE - 14 CE
- Tiberius 14-37
- Caligula 37-41
- Claudius 41-54
- Nero 54-68
- Galba 68-69
- Otho 69
- Vitellius 69
- Vespasian 69-79
The year 69 is known as the year of four emperors.
- Titus 79-81
- Domitian 81-96
- Nerva 96-98
- Trajan 98-117
- Hadrian 117-138
- Antoninus Pius 138-161
- Marcus Aurelius and his brother Lucius Verus 161-169
- Marcus Aurelius alone 169-177
- Marcus Aurelius and his son Commodus 177-180
- Commodus alone 180-192
- Pertinax 193
- Didius Julianus 193
- Septimius Severus 193-198
- Septimius Severus and his son Geta 198-209
- Septimius Severus and his sons Geta and Caracalla 209-211
- Geta alone 211
- Caracalla alone 211-217
- Macrinus 217-218
- Macrinus and his son Diadumenian 218
- Elagabalus (or Heliogabalus) 218-222
- Severus Alexander 222-235
- Maximinius the Thracian 235-238
- Gordian I and his son Gordian II 238
- Balbinus and Pupienus Maximus 238
- Gordian III 238-244
- Philip the Arabian 244-247
- Philip the Arabian and his son Philip II 247-249
- Decius 249-251
- Decius and his son Herennius Etruscus 251
- Hostilian and Trebonianus Gallus 251
- Trebonianus Gallus and his son Velusian 251-253
- Aemilian 253
- Valerian and his son Gallienus 253-260
Valerian was one of the very few who was still alive after the end of his reign.
- Gallienus and his son Saloninus 260
- Gallienus alone 260-268
- Claudius II 268-270
- Quintillus 270
- Aurelian 270-275
- Tacitus 275-276
- Florian 276
- Probus 276-282
- Carus 282-283
- Numerian and his brother Carinus 283-284
- Carinus and Diocletian 284-285
- Diocletian alone 285-286
- Diocletian and Maximian 286-305
Uh oh, now it gets complicated. This was the Tetrarchy with two Augusti as main emperors, east and west, and two Caesares as deputies. I've drawn myself some time-lines to try to work out which reigns overlapped. I am listing only the emperors and co-regents, not their deputies. Maximian, having abdicated with Diocletian in 305, actually resumed the title of Augustus in 307-308 and in 309-310, but if I try to fit him in down here you'll reach out of the chatterbox and throttle me till my eyes bug out, so let's not.
- Galerius and Constantius Chlorus 305-306
- Galerius and Severus 306-307
- Galerius and Maxentius and Constantine the Great 307-308
- Galerius and Maxentius and Constantine the Great and Licinius 308-310
- Galerius and Maxentius and Constantine the Great and Licinius and Maximinus II 310-311
I'm not making this up, you know.
- Maxentius and Constantine the Great and Licinius and Maximinus II 311-312
- Constantine the Great and Licinius and Maximinus II 312-313
- Constantine the Great and Licinius 313-316
- Constantine the Great and Licinius and Valerius Valens 316-317
- Constantine the Great and Licinius 317-324
- Constantine the Great and Martinian 324
- Constantine the Great alone 324-337
- Constantine II and Constans and Constantius II, brothers, 337-340
- Constans and Constantius II 340-350
- Constantius II and Magnentius 350-353
- Constantius II alone 353-360
- Constantius II and Julian the Apostate 360-361
- Julian the Apostate alone 361-363
- Jovian 363-364
- Valentinian I and his brother Valens 364-367
- Valentinian I and Valens and Gratian 367-375
- Valens and Gratian and Valentinian II 375-378
- Gratian and Valentinian II 378-379
- Gratian and Valentinian II and Theodosius the Great 379-383
- Valentinian II and Theodosius the Great and Maximus and Arcadius 383-387
- Valentinian II and Theodosius the Great and Maximus and Arcadius and Victor 387-388
- Valentinian II and Theodosius the Great and Arcadius 388-392
- Theodosius the Great and Arcadius and Eugenius 392-393
- Theodosius the Great and Arcadius and Eugenius and Honorius 393-394
- Theodosius the Great and Arcadius and Honorius 394-395
footnote 17
On the death of Theodosius the empire was permanently divided into independent states, the
Western Roman Empire going to his son Honorius, and Eastern Roman Empire, better known as
The Byzantine Empire, going to his son Arcadius. See under those two nodes for subsequent emperors.
Right, the above list is so confusing that here it is again in a more familiar form, one line per emperor; this means there's lots of overlapping dates. Refer to the above to resolve them; refer to this one below if you just want a simple list. (In case I made a mistake rearranging it, the one above is more accurate.)
- Augustus 27 BCE - 14 CE
- Tiberius 14-37
- Caligula 37-41
- Claudius 41-54
- Nero 54-68
- Galba 68-69
- Otho 69
- Vitellius 69
- Vespasian 69-79
- Titus 79-81
- Domitian 81-96
- Nerva 96-98
- Trajan 98-117
- Hadrian 117-138
- Antoninus Pius 138-161
- Marcus Aurelius 161-180
- Lucius Verus 161-169
- Commodus 177-192
- Pertinax 193
- Didius Julianus 193
- Septimius Severus 193-211
- Geta 198-211
- Caracalla 209-217
- Macrinus 217-218
- Diadumenian 218
- Elagabalus 218-222
- Severus Alexander 222-235
- Maximinius the Thracian 235-238
- Gordian I 238
- Gordian II 238
- Balbinus 238
- Pupienus Maximus 238
- Gordian III 238-244
- Philip the Arabian 244-249
- Philip II 247-249
- Decius 249-251
- Herennius Etruscus 251
- Hostilian 251
- Trebonianus Gallus 251-253
- Velusian 251-253
- Aemilian 253
- Valerian 253-260
- Gallienus 253-268
- Saloninus 260
- Claudius II 268-270
- Quintillus 270
- Aurelian 270-275
- Tacitus 275-276
- Florian 276
- Probus 276-282
- Carus 282-283
- Numerian 283-284
- Carinus 283-285
- Diocletian 284-305
- Maximian 286-305
- Galerius 305-311
- Constantius Chlorus 305-306
- Severus 306-307
- Maxentius 307-312
- Constantine the Great 307-337
- Licinius 308-324
- Maximinus II 310-313
- Valerius Valens 316-317
- Martinian 324
- Constantine II 337-340
- Constans 337-350
- Constantius II 337-361
- Magnentius 350-353
- Julian the Apostate 360-363
- Jovian 363-364
- Valentinian I 364-375
- Valens 364-378
- Gratian 367-383
- Valentinian II 375-392
- Theodosius the Great 379-395
- Maximus 383-388
- Arcadius 383-395
- Victor 387-388
- Eugenius 392-394
- Honorius 393-395