Timeline of Rome

3rd Century AD – Winds of Change in Rome

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The 3rd century AD was a time of tremendous upheaval for Rome. The Severan dynasty gave way to the instability of the so-called “barracks emperors,” while external invasions (Goths, Franks, Alamanni) strained the empire’s borders and a series of plagues ravaged its populace. Diocletian’s rise near century’s end introduced the Tetrarchy, an attempt at structured governance to halt civil wars and ease succession. Meanwhile, Christianity quietly gained adherents, as evidenced by new dioceses—including Manfredonia, Nocera de’ Pagani, and Sora—even though emperors oscillated between persecuting believers or granting them tolerance. Despite the era’s turmoil, the empire adapted through administrative reforms, defensive fortifications (like the Aurelian Walls), and constant efforts to stabilize a beleaguered currency.

Full Chronological Summary (3rd Century AD)

Dioceses Established in the 3rd Century

  • Manfredonia
  • Nocera de’ Pagani
  • Sora

AD 201

  • 245th Olympiad.

AD 203

  • Eruption of Vesuvius.

AD 205

  • 246th Olympiad.

AD 206

  • The bandit leader Bulla Felix roams Italy with ~600 followers.

AD 207

  • Bulla Felix is captured and executed, thrown to wild beasts in the arena.

AD 208

  • Wars in Britain begin against the Pictish tribes.

AD 209

  • 247th Olympiad.
  • Geta is made co-Augustus alongside his father Septimius Severus and brother Caracalla.

AD 211

  • (Feb 4) Emperor Septimius Severus dies in York (Eboracum), aged 64.
  • His sons Caracalla and Geta succeed as co-emperors.
  • Geta is killed in late December (likely at Caracalla’s instigation).

AD 212

  • Caracalla issues the Constitutio Antoniniana, granting civitas (Roman citizenship) to almost all free inhabitants of the empire.

AD 213

  • 248th Olympiad.

AD 214

  • Birth of Aurelian, future emperor famed for reunifying the empire (270–275).

AD 217

  • 249th Olympiad.
  • (Apr 8) Caracalla is assassinated in Cappadocia; the Moorish general Macrinus becomes emperor.
  • (Dec 20) Pope Zephyrinus dies; St. Callixtus I succeeds, opposed by St. Hippolytus—the first Antipope.

AD 218

  • (June 18) Macrinus is overthrown and executed.
  • Elagabalus (Varius Avitus Bassus, age 14) becomes emperor, known for promoting the sun-god Sol Invictus.
  • Silver in the denarius drops to ~43%.

AD 219

  • (Sept 29) Elagabalus arrives in Rome, establishing the cult of Sol Invictus.

AD 220

  • Early Gothic raids begin in Anatolia and the Balkans.

AD 221

  • 250th Olympiad.
  • (June 26) Elagabalus adopts his cousin Alexander Severus, naming him Caesar.

AD 222

  • (Mar 11) Elagabalus is assassinated by the Praetorian Guard. His body is dragged through Rome and thrown into the Tiber; the Senate proclaims damnatio memoriae.
  • Alexander Severus (age 14) becomes emperor, a contrast to Elagabalus’s excesses.
  • Denarius silver content at ~35%.
  • Pope Callixtus I dies—possibly during street violence. St. Urban I succeeds him.
  • A period of Vesuvius activity begins (until ~235).

AD 225

  • 251st Olympiad.

AD 229

  • 252nd Olympiad.

AD 230

  • (July 21) St. Pontianus becomes Pope.

AD 233

  • 253rd Olympiad.

AD 234

  • (Nov 21) St. Anterus becomes Pope after Pontian’s exile. (Alt. date 236).
  • (c.) Ammonius of Alexandria advances Neo-Platonist thought.

AD 235

  • (Mar 18/19) Emperor Alexander Severus is murdered in Germany by troops supporting Maximinus Thrax.
  • The 62-year-old Maximinus is the first “barracks emperor,” from Thrace, of Gothic-Alanic heritage, extremely tall and militaristic, hostile to elites.

AD 236

  • (Jan 3) Pope Anterus dies. On (Jan 10) St. Fabian succeeds him (alt. dates 235/237).

AD 237

  • 254th Olympiad.

AD 238: Year of the Six Emperors

  • At Carthage, Gordian I (80) and Gordian II (46) revolt. They are declared co-Augusti by the Senate.
  • Roman troops loyal to Emperor Maximinus defeat and kill Gordian II (Apr 12); Gordian I commits suicide.
  • Senate names Balbinus and Pupianus co-emperors (Apr 22) and raises Gordian III (14) to Caesar.
  • Balbinus and Pupianus are murdered by the Praetorians; Gordian III becomes sole Augustus (July 29).
  • (Apr) Maximinus is assassinated by his own troops.
  • Denarius silver content ~28%.

AD 241

  • 255th Olympiad.

AD 243

  • Birth of Diocletian, future emperor (284–305).

AD 244

  • (Feb 11) Gordian III is killed by his Praetorian Prefect, Philip the Arab (Marcus Julius Philippus).
  • As Emperor, Philip halts Christian persecutions; Church father Eusebius suggests Philip was a “secret Christian.”
  • Denarius silver content plummets to ~0.5%.

AD 245

  • 256th Olympiad.
  • Plotinus, Neo-Platonist philosopher, arrives in Rome.

AD 248

  • (Apr) Rome celebrates its 1000th anniversary (since traditional founding in 753 BC).
  • Revolts by Iotapianus (in the East) and Pacatianus (in Moesia).

AD 249

  • 257th Olympiad.
  • Emperor Philip the Arab is deposed and killed in a mutiny.
  • Decius becomes emperor.

AD 250: Renewed Persecutions

  • Emperor Decius resumes Christian persecutions.
  • St. Albina is martyred at Formiae near Naples.
  • Eruption on Stromboli.
  • Pope Fabianus and 7 deacons are executed.
  • War with the Goths begins.

AD 251

  • Battle of Abrittus: Decius is killed by the Goths; Trebonianus Gallus succeeds.
  • A new plague (possibly measles) spreads from Carthage to the west, continuing to ~266. At its height, ~5,000 die daily in Rome.
  • (Mar) St. Cornelius becomes Pope, opposed by the Antipope Novatian.
  • Possibly c700,000 inhabitants in Rome, of whom ~1,600 are Christians.
  • Legendary martyrdom accounts (Sts. Alphius, Philadelphus, Cyrinus, Benedicta, and Onesimus) in Sicily and Campania are generally deemed unhistorical.

AD 252

  • (Feb 1–9) Eruption of Mt. Etna.
  • St. Agatha is martyred in Sicily (alt. date 251).
  • S. Agostino becomes Bishop of Capua (to 260).

AD 253

  • 258th Olympiad.
  • Trebonianus Gallus exiles Pope Cornelius to Centum Cellae, where the pope dies in June.
  • (June 25) St. Lucius I becomes Pope.
  • Emperor Trebonianus Gallus is killed; Aemilianus briefly rules before being toppled by Valerian (age ~60).
  • Valerian decrees death for all Christian clergy.

AD 254

  • (May 12) Stephen I becomes Pope.

AD 255

  • Cyprian, bishop of Carthage, writes De Mortalitate, describing a widespread pandemic with symptoms like vomiting, sore throat, fever, gangrene.
  • Letters mention unseasonably cold and wet conditions that diminish harvests.

AD 256

  • Plague extends into eastern provinces, including Alexandria, causing high mortality and some conversions to Christianity.

AD 257

  • 259th Olympiad.
  • Emperor Valerian launches further persecutions of Christians.
  • (Aug 30) St. Sixtus II becomes Pope.
  • Gothic and Frankish raids intensify across the Danube and Rhine.

AD 258

  • (Aug 6) Pope Sixtus II is beheaded on Valerian’s orders.

AD 259

  • (July 22) St. Dionysius becomes Pope (alt. date 260).
  • Emperor Valerian is captured by Persia’s Shapur I at Edessa.
  • Gallienus (Valerian’s son) rules alone, ending persecutions of Christians.
  • Pope Dionysius reorganizes the Church in Rome.
  • S. Quinto becomes Bishop of Capua (to 271).

AD 260

  • 260th Olympiad.

AD 262

  • St. Agrippina is martyred, possibly in 256 (traditions vary). Her relics are taken to Mineo, Sicily.

AD 263

  • Neo-Platonist Porphyry comes to Rome.

AD 265

  • 261st Olympiad.

AD 268

  • Emperor Gallienus besieges the rebel Aureolus at Mediolanum (Milan). Gallienus is murdered by his own men.
  • General Claudius Gothicus defeats Aureolus and becomes emperor.
  • Goths ravage Greece (Athens, Sparta, Corinth).
  • (Dec 26) Pope St. Dionysius dies.
  • A slave revolt in Sicily (smaller than earlier centuries) and rural banditry prove hard to quell.

AD 269

  • 262nd Olympiad.
  • Emperor Claudius II defeats a major Gothic invasion in the Balkans.
  • (Jan 5) St. Felix I becomes Pope.

AD 270

  • Philosopher Plotinus dies in Campania.
  • Romans abandon the Dacia province (north of the Danube). They found a new “Dacia” south of the river for displaced Roman settlers.
  • Emperor Claudius II dies of plague at Sirmium; his brother Quintillus succeeds but soon commits suicide.
  • Aurelian (Lucius Domitius Aurelianus) becomes emperor.
  • Denarius silver content collapses to ~0.02%.

AD 271

  • Emperor Aurelian builds the Aurelian Wall around Rome to repel invaders.
  • He repels Alamanni invaders.
  • Diocese of Sora is established.

AD 273

  • 263rd Olympiad.
  • Aurelian reconquers Palmyra, capturing Zenobia and restoring the East to Roman rule.
  • Rome increases the daily free bread ration to ~1.5 lb/person and begins distributing pork fat as well.

AD 274

  • Aurelian defeats the Gallic Empire under Tetricus, reuniting Gaul with Rome.
  • Birth of Constantine I (the Great), future emperor.

AD 275

  • (Jan 4) St. Eutychian becomes Pope.
  • (Jan 25) Emperor Aurelian is assassinated on the eve of a Persian campaign; the Senate forces a senator, Tacitus, to become emperor.
  • Another devastating plague spreads through the army.
  • Diocese of Sora is formally recognized (per tradition).

AD 276

  • Emperor Tacitus is killed in a mutiny, succeeded briefly by Florianus, who is also murdered.
  • Probus takes the throne.

AD 277

  • 264th Olympiad.

AD 280

  • The city of Syracuse is plundered by Frankish raiders.

AD 281

  • 265th Olympiad.

AD 282

  • Emperor Probus is killed in a revolt.
  • Carus succeeds him as emperor.

AD 283

  • Emperor Carus is killed, reportedly by lightning.
  • Sons Carinus and Numerian succeed him.
  • (Dec 17) St. Caius (Gaius) becomes Pope.

AD 284

  • Emperor Numerian dies in the East.
  • Diocletian (age ~39) is proclaimed Emperor (Aug 29).
  • Diocletian initiates the Tetrarchy concept (dividing authority between an eastern and a western Augustus, each with a Caesar).

AD 285

  • 266th Olympiad.

AD 286

  • Maximian is appointed co-Augustus in the West.
  • Carausius declares himself emperor in Britain.

AD 287

  • Imperial decree outlaws Manichaeism.

AD 288

  • Constantius II (future emperor) is born (some confusion with different sources—possibly a misdated note, as Constantius II is more commonly listed as born in AD 317, so this line might be anachronistic or refer to a different person).

AD 289

  • 267th Olympiad.

AD 293

  • 268th Olympiad.
  • (Mar 1) Constantius I Chlorus and Galerius are named Caesars under Diocletian and Maximian.

AD 295

  • Eruption on Ischia.

AD 296

  • Constantius I Chlorus retakes Britain for the empire.
  • (June 30) Marcellinus becomes Pope. Later chroniclers accuse him of apostasy by offering pagan sacrifices.

AD 297

  • 269th Olympiad.

AD 298

  • Christians are expelled from the Roman army (the ongoing lead-up to Diocletian’s later persecutions).

AD 300

  • Christians possibly constitute 2–3% of the empire’s population.
  • S. Aristeo becomes Bishop of Capua (to 303).

Key Takeaways

  1. Severan Dynasty and Beyond
    • Caracalla’s Constitutio Antoniniana (AD 212) granted widespread citizenship.
    • The empire destabilized following Severus and degenerated into crises under Elagabalus, leading to more military rule.
  2. Barracks Emperors
    • From Maximinus Thrax (235) onward, short-lived emperors rose and fell through coup or mutiny. Wars on multiple fronts (Goths, Franks, Persia) weakened the empire.
  3. Economic Strain & Currency Debasement
    • The silver denarius’s purity dropped sharply—eventually near worthless (~0.02% silver).
    • Plagues and invasions disrupted agriculture, forcing repeated famine relief efforts.
  4. Rise of Christianity
    • Despite episodic persecutions (Decius, Valerian, etc.), the Christian population grew, establishing new dioceses (Manfredonia, Nocera de’ Pagani, Sora).
    • Debates over apostasy and leadership marked internal Church conflicts (Antipopes Novatian, Hippolytus).
  5. Military Reorganization & the Tetrarchy
    • Emperor Diocletian (from 284) reorganized the administration, forming the Tetrarchy to stabilize succession and border defense.
    • Efforts to restore the empire’s strength culminated in new fortifications (Aurelian Walls) and leadership structures.

By AD 300, Rome stood on the verge of Diocletian’s sweeping administrative and social reforms, foreshadowing a transformed empire of the 4th century.