Ancient Rome · TURNING POINT · 286

Diocletian’s Tetrarchy (286)

On the Ancient Rome map as “Diocletian’s court”

AD 286 — Diocletian refounds the empire from his court at Nicomedia rather than Rome. Four emperors, twelve dioceses, a doubled army and taxes in kind make survival possible at the cost of a heavier state.

When: AD 286
Type: Turning point
Chapter: Diocletian and Constantine (chapter 9 of Ancient Rome)
Atlas: The Rise and Fall of Rome, 264 BC – AD 476

Open this map in the interactive atlas →

Chapter 9 is included with every paid plan. WW2 is free in full, and chapter 1 of every atlas is free. A free account opens 3 more chapters a day. Starter, at $9 a month, opens all 21 with no daily limit — see the plans.

Free printable Ancient Rome study guide, sent by email ↓

Map showing Diocletian’s Tetrarchy (286), turning point in The Rise and Fall of Rome, 264 BC – AD 476 — TURNING POINT · THE RISE AND FALL OF ROME, 264 BC – AD 476

These maps are reconstructed from published sources · Cliopatria v0.2.1 · English Heritage: Hadrian’s Wall facts and FAQs · Natural Earth physical coastlines and rivers · Pleiades: ancient places and Hadrian’s Wall forts · UNESCO: Frontiers of the Roman Empire

Source details

Cliopatria contributors / Seshat Global History Databank. Selected, combined, and reprojected by Maps of History; dated adjustments are recorded per layer.. CC BY 4.0
English Heritage, facts checked by Dr Frances McIntosh (2026): wall endpoints and fort sequence.. Historical evidence citation; no copyrighted map traced
Made with Natural Earth. Modern physical geography is a coastline/river reference, not evidence of ancient sovereignty.. Public domain
Pleiades contributors; A. S. Esmonde Cleary, R. Talbert and subsequent editors (individual record credits retained in the review). Wall route reconstructed through published fort locations.. CC BY 3.0
UNESCO World Heritage Centre: frontier-system identification and dates.. Historical evidence citation; no map copied

Displayed geometry: 312 (chapter-ch9-312); chapter framing: 312. The map shows the moment selected for the chapter, even when the chapter spans several events.

reconstruction: 312 · reconstruction: AD122 onward · reconstruction: Modern physical shoreline reference · reconstruction: Roman Rhine–Danube frontier system; changing over time · vector: -630 to 337 · vector: 106 to 370 · vector: 224 to 346 · vector: 270 to 401 · vector: 283 to 357 · vector: 283 to 454 · vector: 287 to 366 · vector: 287 to 386 · vector: 287 to 396 · vector: 299 to 401 · vector: 306 to 323 · vector: 306 to 346 · vector: 306 to 395 · vector: 311 to 312 · vector: 311 to 336 · vector: 78 to 370

Layer records and reconstruction methods