The emperors who ruled the Roman Empire for the longest periods. This comprehensive dataset is meticulously compiled from verified global sources and updated regularly. Use the sorting and filtering tools to explore the data, or export it as CSV for deeper analysis. All figures are cross-referenced with authoritative international databases.
| Rank ⇵ | Emperor ⇵ | Reign Length ⇵ | Era ⇵ |
|---|---|---|---|
| 1 | Augustus | 40 Years, 7 Months | 27 BC – 14 AD |
| 2 | Theodosius II | 42 Years | 408 – 450 AD |
| 3 | Constantine I (The Great) | 30 Years, 10 Months | 306 – 337 AD |
| 4 | Antoninus Pius | 22 Years, 7 Months | 138 – 161 AD |
| 5 | Tiberius | 22 Years, 6 Months | 14 – 37 AD |
| 6 | Justinian I | 38 Years, 3 Months | 527 – 565 AD |
| 7 | Honorius | 28 Years | 395 – 423 AD |
| 8 | Hadrian | 20 Years, 11 Months | 117 – 138 AD |
| 9 | Trajan | 19 Years, 6 Months | 98 – 117 AD |
| 10 | Diocletian | 20 Years, 5 Months | 284 – 305 AD |
| 11 | Marcus Aurelius | 19 Years | 161 – 180 AD |
| 12 | Domitian | 15 Years | 81 – 96 AD |
| 13 | Claudius | 13 Years, 9 Months | 41 – 54 AD |
| 14 | Septimius Severus | 17 Years, 10 Months | 193 – 211 AD |
| 15 | Valentinian I | 11 Years, 9 Months | 364 – 375 AD |
| 16 | Vespasian | 9 Years, 6 Months | 69 – 79 AD |
| 17 | Gallienus | 15 Years (inc. joint) | 253 – 268 AD |
| 18 | Nero | 13 Years, 8 Months | 54 – 68 AD |
| 19 | Caracalla | 19 Years (inc. joint) | 198 – 217 AD |
| 20 | Constantius II | 24 Years | 337 – 361 AD |
| 21 | Commodus | 15 Years (inc. joint) | 177 – 192 AD |
| 22 | Probus | 6 Years, 2 Months | 276 – 282 AD |
| 23 | Gordian III | 5 Years, 9 Months | 238 – 244 AD |
| 24 | Alexander Severus | 13 Years | 222 – 235 AD |
| 25 | Maximian | 19 Years (joint) | 286 – 305 AD |
| 26 | Valens | 14 Years, 5 Months | 364 – 378 AD |
| 27 | Valentinian III | 30 Years | 425 – 455 AD |
| 28 | Leo I (The Thracian) | 17 Years | 457 – 474 AD |
| 29 | Zeno | 17 Years | 474 – 491 AD |
| 30 | Anastasius I | 27 Years | 491 – 518 AD |