“The Roman Empire” did not exist as such, being a useful term we use to describe a set that exists only as a result of our definition. Nonetheless, our terms are useful to us, and are not wholly without descriptive force. There really were autocrats who ruled over the polity that grew organically out of the Roman Republic. As someone interested in Roman political history, I decided that I would find it useful for my reading to have a list of the Emperors who I personally consider to be “canonical”, so as to help frame my understanding of the events. This list will be very similar to the standard lists, but not quite. For my purposes, they should have the following properties:

Autocracy

The claimant must have been in sole or primary possession of the levers of state power for some period. Thus no junior-only Emperors or inferior co-Emperors, and no failed usurpers, even if retrospectively legitimised, and no one who had the nominal authority of the Senate but no actual authority.

Internal

The claimant must have been internal to the Empire, the polity that grew organically from the Roman Empire. That is, we can exclude the Ottoman claim for our purposes, not because of any supposed invalidity or bias in favour of “the West”, but because Mehmed II was external to the Roman continuity. Certainly the “Holy” Roman claim can be passed over with a chuckle. I have also for this reason excluded the Latin Empire.

Translatio Imperii

As only one person can ever hold autocratic power at any one time, it makes sense for a formalised list like this to use employ translatio imperii in which there is at most one individual with autocratic authority. Similar concepts have long existed elsewhere, such as the Chinese Mandate of Heaven or the Sumerian Kingship. Although at many times no one exercised full autocratic authority, everything is scalar, so I have selected the individual I felt to be furthest along the autocratic scale, not necessarily the “legitimate” monarch, especially in the case of child Emperors.

I start my list with Gaius Julius Cæsar, because there is no particular reason to exclude him. Julius was undisputed autocrat of Rome, dictator perpetuo. He was imperator and pontifex maximus and pater patriae and praefectura morum. The Roman Emperors thereafter all saw themselves as following in his footsteps, as evidenced by taking his name, Caesar, as proof of their imperial power. My view is that the burden of proof lies on those who would exclude Julius from the list.

Yes, this list will continue to be arbitrary, and I may change it at any time. The grouping names are for my convenience, indicating the main feature of that period. Any comments, please speak up.

• Julio-Claudians (6) [49BC-68AD]
1. Julius Caesar [49-44BC]
2. Augustus [44BC-14AD]
3. Tiberius [14-37]
4. Caligula [37-41]
5. Claudius [41-54]
6. Nero [54-68]
• Y4E & Flavians (6) [68-96]
7. Galba [68-69]
8. Otho [69]
9. Vitellius [69]
10. Vespasian [69-79]
11. Titus [79-81]
12. Domitian [81-96]
• Nerva-Antonines (6) [96-192]
13. Nerva [96-98]
14. Trajan [98-117]
15. Hadrian [117-138]
16. Antoninus Pius [138-161]
17. Marcus Aurelius [161-180]
18. Commodus [180-192]
• Y5E & Severans (6) [193-235]
19. Pertinax [193]
20. Septimius Severus [193-211]
21. Caracalla [211-217]
22. Macrinus [217-218]
23. Elagabalus [218-222]
24. Severus Alexander [222-235]
• Crisis of the Third Century (7) [235-270]
25. Maximinus (Thrax) [235-238]
26. Gordian “III” [238-244]
27. Philip (the Arab) [244-249]
28. Decius [249-251]
29. Trebonianus Gallus [251-253]
30. Valerian [253-260]
31. Gallienus [260-268]
• Aurelian Recovery (7) [270-285]
32. Claudius (Gothicus) [268-270]
33. Aurelian [270-275]
34. Tacitus [275-276]
35. Florianus [276]
36. Probus [276-282]
37. Carus [282-283]
38. Carinus [283-285]
• Diocletian-Constantinians (7) [285-364]
39. Diocletian [285-305]
40. Galerius [305-311]
41. Licinius [311-314]
42. Constantine (the Great) [314-337]
43. Constantius II [337-361]
44. Julian (the Apostate) [360-363]
45. Jovian [363-364]
• Valentinian-Theodosians (7) [364-457]
46. Valentinian I [364-375]
47. Valens [375-378]
48. Theodosius I [379-395]
49. Arcadius [395-404]
50. Anthemius (regent) [404-414]
51. Theodosius II [414-450]
52. Marcian [450-457]
• Leonids (4) [457-518]
53. Leo I [457-474]
54. Zeno [474-475, later 476-491]
55. Basiliscus [475-476]
54. Zeno (restored) [476-491]*
56. Anastasius I (Dicorus) [491-518]
• Justinians (6) [518-610]
57. Justin I [518-527]
58. Justinian I [527-565]
59. Justin II [565-578]
60. Tiberius II (Constantine) [578-582]
61. Maurice [582-602]
62. Phocas [602-610]
• Heraclians (6) [610-695]
63. Heraclius [610-641]
64. Constantine III [641]
65. Martina (regent) [641]
66. Constans II [641-668]
67. Constantine IV [668-685]
68. Justinian II [685-695, later 705-711]
• 20Y Anarchy (5) [695-717]
69. Leontios [695-698]
70. Tiberios III (Apsimar) [698-705]
68. Justinian II (restored) [705-711]
71. Philippikos (Bardanes) [711-713]
72. Anastasios II (Artemios) [713-715]
73. Theodosios III [715-717]
• Isaurians (5) [717-802]
74. Leo III (Konon the Isaurian) [717-741]
75. Constantine V (the Dung-Named) [741-775]
76. Leo IV (the Khazar) [775-780])
77. Irene (of Athens, regent) [780-790]
78. Constantine VI [790-797]
77. Irene (of Athens) [797-802, previously regent 780-790]*
• Nikephorian-Amorians (6) [802-867]
79. Nikephorus I [802-811]
80. Michael I (Rhangabe) [811-813]
81. Leo V (the Armenian) [813-820]
82. Michael II [820-829]
83. Theophilus [829-842]
84. Michael III [842-867]
• Early Macedonians (6) [867-944]
85. Basil I (the Macedonian) [867-886]
86. Leo VI (the Wise) [886-912]
87. Alexander [912-913]
88. Nicholas (Mystikos, regent) [913-914]
89. Zoe (Karbonopsina, regent) [914-919]
90. Romanos I (Lekapenos) [919-944]
• Middle Macedonians (6) [944-1025]
91. Constantine VII (Porphyrogenitus) [944-959]
92. Romanos II [959-963]
93. Nikephorus II (Phokas) [963-969]
94. John I (Tzimiskes) [969-976]
95. Basil II [976-1025]
96. Constantine VIII [1025-1028]
• Zoë and Theodora (6) [1028-1056]
97. Romanos III (Argyros) [1028-1034]
98. Michael IV [1034-1041]
99. Michael V [1041-1042]
100. Zoë (Porphyrogenita) [1042]
101. Constantine IX (Monomachos) [1042-1055]
102. Theodora (Porphyrogenita) [1055-1056]
• Doukids (7) [1056-1081]
103. Michael VI (Bringas) [1056-1057]
104. Isaac I (Komnenos) [1057-1059]
105. Constantine X (Doukas) [1059-1067]
106. Eudokia (Makrembolitissa, regent) [1067-1068]
107. Romanos IV (Diogenes) [1068-1071]
108. Michael VII (Doukas) [1071-1078]
109. Nikephoros III (Botaneiates) [1078-1081]
• Komnenids (5) [1081-1185]
110. Alexios I [1081-1118]
111. John II [1118-1143]
112. Manuel I (the Great) [1143-1180]
113. Maria (of Antioch, regent) [1180-1182]
114. Andronikos I [1182-1185]
• Angelid-Laskarids (6) [1185-1258]
115. Isaac II (Angelos) [1185-1195]
116. Alexios III (Angelos) [1195-1203]
117. Alexios IV (Angelos) [1203-1204]
118. Theodore I (Laskaris) [1204-1221]
119. John III (Doukas Vatatzes) [1221-1254]
120. Theodore II (Laskaris) [1254-1258]
• Palaiologans (11) [1258-1453]
121. Michael VIII [1258-1282]
122. Andronikos II [1282-1328]
123. Andronikos III [1328-1341]
124. Anna (of Savoy, regent) [1341-1347]
125. John VI (Kantakouzenos) [1347-1354]
126. John V [1354-1376, later 1379-1390, 1390-1391]
127. Andronikos IV [1376-1379]
126. John V (restored) [1379-1390, later 1390-1391]
128. John VII [1390]
126. John V (restored) [1390-1391]
129. Manuel II [1391-1425]
130. John VIII [1425-1448]
131. Constantine XI [1449-1453]