The Chronology of the Roman Emperors until the Fall of Rome in AD 476 later emperors (for example Constantius) are placed on the chronology on becoming Augusti, not on their being appointed Caesares
Augustus 27 BC- AD14
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 180-192
Pertinax 193
Didius Julianus 193
Niger, Albinus, Septimius Severus
Septimius Severus 193-211
Caracalla 211-217
Geta 211
Macrinus 217-218
Elagabalus 218-222
Alexander Severus 222-235
Maximinus Thrax 235-238
Gordian, Gordian II 238
Pupienus, Balbinus 238
Gordian III 238-244
Phillippus Arabs 244-249
Decius 249-251
Trebonianus Gallus 251-253
Aemilius Aemilianus 253
Valerian 253-260
Gallienus 253-268
Claudius II 268-270
Quintillus 270
Aurelian 270-275
The Gallic Empire follows death of Valerian
Postumus 260-269
Laelianus 269
Marius 269
Victorinus 269-271
Domitianus 271
Tetricus 271-274
Tacitus 275-276
Florianus 276
Probus 276-282
Carus 282-283
Numerian 283-284
Carinus 283-285
Diocletian 284-286 (splits empire, rules east)
Western Empire after split by Diocletian
Maximian 286-305
Constantius I 305-306
Severus II 306-307
Constantine 307-337
Maxentius 306-312
Maximian returned 307-308
Eastern Empire after split by Diocletian
Diocletian 286-305
Galerius 305-311
Maximinus Daia 310-313
Licinius 308-324
Re-United Empire reunited by Constantine's defeat of Licinius
