Those individuals who have historically been accepted as the 'official' emperors are in bold; usurpers or other claimants generally excluded from regnal lists are in italics. Unless otherwise stated; the succession to the title was from an emperor to his nominated heir; and death was by natural causes.
The Principate
Reign
Incumbent
Notes
16 January 27 BC to 19 August AD 14
Augustus
19 August 14 to 16 March 37
Tiberius
18 March 37 to 24 January 41
Caligula
Murdered by Praetorian Guard
24 January 41 to 13 October 54
Claudius
Poisoned by his wife Agrippina, mother of Nero
13 October 54 to 11 June 68
Nero
Committed suicide
Reign
Incumbent
Notes
8 June 68 to 15 January 69
Galba
Murdered in favour of
Otho
15 January 69 to 16 April 69
Otho
Committed suicide
2 January 69 to 20 December 69
Vitellius
Murdered in favour of
Vespasian
Reign
Incumbent
Notes
1 July 69 to 24 June 79
Vespasian
24 June 79 to 13 September 81
Titus
Possibly assassinated by Domitian
14 September 81 to 18 September 96
Domitian
Assassinated
Reign
Incumbent
Notes
18 September 96 to 27 January 98
Nerva
Proclaimed emperor by senate
28 January 98 to 7 August 117
Trajan
11 August 117 to 10 July 138
Hadrian
10 July 138 to 7 March 161
Antoninus Pius
7 March 161 to 17 March 180
Marcus Aurelius
7 March 161 to March 169
Lucius Verus
Co-emperor with
Marcus Aurelius
175
Avidius Cassius
Usurper; ruled in Egypt and Syria; murdered by his own army
177 to 31 December 192
Commodus
Assassinated
Reign
Incumbent
Notes
1 January 193 to 28 March 193
Pertinax
Proclaimed emperor by senate; murdered by Praetorian Guard
28 March 193 to 1 June 193
Didius Julianus
Proclaimed emperor by Praetorian Guard; executed on orders of the Senate
9 April 193 to 4 February 211
Septimius Severus
Proclaimed emperor by Pannonian troops; accepted by senate
193 to 194/195
Pescennius Niger
Proclaimed emperor by Syrian troops, defeated in battle by
Septimius Severus
193/195 to 197
Clodius Albinus
Proclaimed emperor by British troops, defeated in battle by
Septimius Severus
198 to 8 April 217
Caracalla
Assassinated at the behest of
Macrinus
209 to 4 February 211
Geta
Co-emperor with
Caracalla; assassinated on orders of
Caracalla
11 April 217 to June 218
Macrinus
Proclaimed himself emperor; executed on orders of
Elagabalus
May 217 to June 218
Diadumenian
Junior co-emperor under
Macrinus; executed
June 218 to 222
Elagabalus
Proclaimed emperor by army; murdered by his own troops
13 March 222 to
?March 235
Alexander Severus
Murdered by his own troops
Reign
Incumbent
Notes
February/March 235 to March/April 238
Maximinus Thrax
Proclaimed emperor by the army; murdered by
Praetorian Guard
earlyJanuary/March 238 to
lateJanuary/April 238
Gordian I
Proclaimed emperor in Africa; committed suicide after
Gordian II's death
earlyJanuary March 238 to
lateJanuary/April 238
Gordian II
Proclaimed emperor with
Gordian I, killed in battle
earlyFebruary 238 to
earlyMay 238
Pupienus
Proclaimed joint emperor by senate; murdered by
Praetorian Guard
earlyFebruary 238 to
earlyMay 238
Balbinus
Proclaimed joint emperor by senate; murdered by
Praetorian Guard
May 238 to February 244
Gordian III
Nephew of
Gordian II; death unclear, probably murdered
240
Sabinianus
Usurper; proclaimed himself emperor; defeated in battle
February 244 to September/October 249
Philip the Arab
Proclaimed emperor after death of
Gordian III; killed in battle by
Decius
248
Pacatianus
Usurper; proclaimed himself emperor; murdered by his own soldiers
248 to 249
Iotapianus
Usurper; proclaimed himself emperor in the east; murdered by his own soldiers
248? or 253?
Silbannacus
Usurper; details essentially unknown
249 to June 251
Decius
Killed in battle
249 to 252
Priscus
Proclaimed himself emperor in the east in opposition to
Decius
250 to 250
Licinianus
Usurper; proclaimed emperor in Rome; rebellion suppressed
early251 to June 251
Herennius Etruscus
Junior co-emperor under
Decius; killed in battle
251
Hostilian
Son of
Decius; died of plague
June 251 to August 253
Gallus
Proclaimed emperor by his troops after Decius's death; murdered by them in favour of Aemilianus
July 251 to August 253
Volusianus
Junior co-emperor under
Gallus; murdered by army
August 253 to October 253
Aemilian
Proclaimed emperor by his troops; murdered by them in favour of
Valerian
253 to June 260
Valerian
Proclaimed emperor by his troops; captured in battle by the
Persians; died in captivity
253 to September 268
Gallienus
Junior co-emperor under
Valerian to 260; probably murdered by his generals
260
Saloninus
Son of
Gallienus; proclaimed emperor by army; murdered shortly after by troops of
Postumus
June 260 (or 258)
Ingenuus
Usurper; proclaimed himself emperor after
Valerian's capture; defeated in battle
260
Regalianus
Usurper; proclaimed emperor after
Ingenuus's defeat; fate unclear
260 to 261
Macrianus Major
Usurper; proclaimed emperor by eastern army; defeated and killed in battle
260 to 261
Macrianus Minor
Usurper; son of
Macrianus Major; defeated and killed in battle
260 to 261
Quietus
Usurper; son of
Macrianus Major; defeated and killed in battle
261 to 261 or 262
Mussius Aemilianus
Usurper; proclaimed himself emperor after the defeat of the Macriani; defeated and executed
268 to 268
Aureolus
Usurper; proclaimed himself emperor after
Gallienus's death; surrendered to
Claudius II Gothicus; murdered by Praetorian Guard
268 to August 270
Claudius II Gothicus
Proclaimed emperor by the army
August 270 to September 270
Quintillus
Proclaimed himself emperor; cause of death unclear
August 270 to 275
Aurelian
Proclaimed emperor by army; murdered by the
Praetorian Guard
271 to 271
Septimius
Usurper; proclaimed emperor in
Dalmatia; killed by his own soldiers
November/December 275 to July 276
Tacitus
Appointed emperor by the Senate; possibly assassinated
July 276 to September 276
Florianus
Proclaimed emperor by the western army; murdered by his troops
July 276 to
lateSeptember 282
Probus
Proclaimed emperor by the eastern army; murdered by his own soldiers in favour of
Carus
280
Julius Saturninus
Usurper; proclaimed emperor by his troops; then killed by them
280
Proculus
Usurper; proclaimed himself emperor at the request of the people of
Lugdunum; executed by
Probus
280
Bonosus
Usurper; proclaimed himself emperor; defeated by
Probus and committed suicide
September 282 to July/August 283
Carus
Proclaimed emperor by Praetorian guard
spring 283 to summer 285
Carinus
Son of Carus; co-emperor with
Numerian; fate unclear
July/August 283 to November 284
Numerian
Son of Carus; co-emperor with
Carinus; probably murdered
Reign
Incumbent
Notes
260 to 268
Postumus
Declared himself emperor after
Valerian's death; killed by his own troops
268 to 268
Laelianus
Proclaimed himself emperor in opposition to Postumus; defeated and killed by Postumus
269 to 269
Marius
Proclaimed himself emperor after Postumus's death
269 to 271
Victorinus
Proclaimed emperor after Marius's death
270 to 271
Domitianus
Proclaimed himself emperor of the
Gallic Empire
271 to 274
Tetricus I
Nominated heir to Victorinus
Reign
Incumbent
Notes
286 to 293
Carausius
Declared himself emperor; assassinated by
Allectus
293 to 297
Allectus
Declared himself emperor after
Carausius's death; defeated by
Constantius Chlorus
Reign
Incumbent
Notes
20 November 284 to 1 May 305
Diocletian
Declared emperor by the army after Numerian's death; Abdicated
1 April 286 to 1 May 305
Maximian
Made co-emperor ('Augustus') with
Diocletian; abdicated
1 May 305 to 25 July 306
Constantius I Chlorus
Made junior co-emperor ('Caesar') under
Maximian; became Augustus after his abdication
1 May 305 to May 311
Galerius
Made junior co-emperor ('Caesar') under
Diocletian; became Augustus after his abdication
August 306 to 16 September 307
Severus II
Made junior co-emperor ('Caesar') under
Constantius Chlorus; became Augustus after his death; executed by
Maxentius
28 October 306 to 28 October 312
Maxentius
Son of
Maximian; proclaimed Augustus by
Praetorian Guard; defeated in battle by
Constantine I
de jure: 307,
de facto 312 to 22 May 337
Constantine I
Son of
Constantius Chlorus; proclaimed Augustus by army
308-
309?/
311?
Domitius Alexander
Proclaimed emperor in Africa; defeated in battle by
Maxentius
11 November 308 to 18 September 324
Licinius
Appointed Augustus by
Galerius; deposed by
Constantine I and executed
1 May 311 to July/August 313
Maximinus Daia
Made junior co-emperor ('Caesar') under
Galerius; became Augustus after his death; defeated in battle by Licinius and committed suicide
December 316 to 1 March 317
Valerius Valens
Appointed co-Augustus by
Licinius; executed by
Licinius
July to 18 September 324
Martinianus
Appointed co-Augustus by
Licinius; deposed by
Constantine I and executed
337 to 340
Constantine II
Son of
Constantine I; co-emperor with his brothers; killed in battle
337 to 361
Constantius II
Son of
Constantine I; co-emperor with his brothers
337 to 350
Constans I
Son of
Constantine I; co-emperor with his brothers, killed by
Magnentius
January 350 to 11 August 353
Magnentius
Usurper; proclaimed emperor by the army; defeated by
Constantius II and committed suicide
c. 350
Vetranio
Proclaimed himself emperor against
Magnentius; recognized by
Constantius II but then deposed
c. 350
Nepotianus
Proclaimed himself emperor against
Magnentius, defeated and executed by
Magnentius
November 361 to June 363
Julian
Cousin of
Constantius II; made Caesar by Constantius, then proclaimed Augustus by the army; killed in battle
363 to 17 February 364
Jovian
Proclaimed emperor by the army after
Julian's death
Reign
Incumbent
Notes
26 February 364 to 17 November 375
Valentinian I
Proclaimed emperor by the army after
Jovian's death
28 March 365 to 9 August 378
Valens
Made co-emperor in the east by his brother
Valentinian I; killed in battle
September 365 to 27 May 366
Procopius
Usurper; Proclaimed himself emperor; defeated and executed by
Valens
24 August 367 to 383
Gratian
Son of
Valentinian I; assassinated
375 to 392
Valentinian II
Son of
Valentinian I; deposed by
Arbogast and died in suspicious circumstances
383 to 388
Magnus Maximus
Usurper; proclaimed emperor by troops; at one time recognized by
Theodosius I, but then deposed and executed
c.386 to 388
Flavius Victor
Son of Magnus Maximus, executed on orders of
Theodosius I
392 to 394
Eugenius
Usurper; proclaimed emperor by army under
Arbogast; defeated in battle by
Theodosius I
Reign
Incumbent
Notes
379 to 17 January 395
Theodosius I
Made co-emperor for the east by
Gratian
383 to 408
EAST
Arcadius
Appointed co-emperor with his father
Theodosius I; sole emperor for the east from January 395
23 January 393 to 15 August 423
WEST
Honorius
Appointed Augustus for the west by his father
Theodosius I
407 to 411
WEST
Constantine III
Usurper; proclaimed emperor in Britain; defeated by
Constantius III
409 to 411
WEST
Constans II
Usurper; made emperor by his father
Constantine III; killed in battle
409 and 414 to 415
WEST
Priscus Attalus
Usurper; twice proclaimed emperor by
Visigoths under
Alaric and twice deposed by
Honorius
409 to 411
WEST
Maximus
Usurper; proclaimed emperor in Spain; abdicated
411 to 413
WEST
Jovinus
Usurper; proclaimed emperor after
Constantine III's death, executed by
Honorius
412 to 413
WEST
Sebastianus
Usurper; appointed co-emperor by
Jovinus, executed by
Honorius
408 to 450
EAST
Theodosius II
Son of
Arcadius
421 to 421
WEST
Constantius III
Son-in-law of
Theodosius I; appointed co-emperor by
Honorius
423 to 425
WEST
Joannes
Proclaimed western emperor, initially undisputed; defeated and executed by
Theodosius II in favour of
Valentinian III
425 to 16 March 455
WEST
Valentinian III
Son of
Constantius III; appointed emperor by
Theodosius II; assassinated
Reign
Incumbent
Notes
17 March 455 to 31 May 455
Petronius Maximus
Proclaimed himself emperor after
Valentinian III's death; murdered
June 455 to 17 October 456
Avitus
Proclaimed emperor by the
Visigoth king
Theoderic II; deposed by
Ricimer
457 to 2 August 461
Majorian
Appointed by
Ricimer; deposed and executed by
Ricimer
461 to 465
Libius Severus
Appointed by
Ricimer; deposed and executed by
Ricimer
12 April 467 to 11 July 472
Anthemius
Appointed by
Ricimer; deposed and executed by
Ricimer
July 472 to 2 November 472
Olybrius
Appointed by
Ricimer
5 March 473 to June 474
Glycerius
Appointed by
Gundobad; deposed by
Julius Nepos
June 474 to 25 April 480
Julius Nepos
Appointed by eastern emperor
Leo I; deposed in Italy by
Orestes in 475; continued to be recognised as lawful emperor in Gaul and Dalmatia until his murder in 480
31 October 475 to 4 September 476
Romulus Augustus
(
Romulus Augustulus)
Son of
Orestes; deposed by
Odoacer; fate unknown