'The Decline' Chronology 193-194 Second crisis of the Empire: second year of four emperors, Pertinax, Clodius Albinus, Pescennius Niger, Septimius Severus 193-211 Septimius Severus emperor, initiating Severan dynasty 194 Severus recognizes Albinus as Caesar but marches against Pescennius. Defeat and death of Pescennius. His followers hold out for two years in Byzantium. 195-196 Parthian campaign 197 Contest of Severus and Albinus. Death of Albinus at Battle of Lugdunum. Severus sole emperor 198 Severus organizes Praetorian Guard under his own command 199 The province of Mesopotamia is brought back into the Empire 199-200 Septimius Severus in Egypt 204 Secular Games (Ludi saeculares) celebrated throughout the Empire 206-207 Septimius Severus in Africa 208-211 Septimius Severus heads campaign in Britain and dies there 211-217 Caracalla emperor 212 The Constitutio Antoniniana, issued by Caracalla, confers citizenship on all free men in the Empire 216 War again breaks out in Parthia 217-218 Macrinus and his ten-year-old son Diadumenianus co-emperors after murder of Caracalla 218-222 Elagabalus emperor, reestablishes Severan rule 222-235 Alexander Severus emperor 224-241 Artaxerxes I reigns over the new Persian empire of the Sassanids (or Sasanians) 230-232 Campaign against the Sassanids 235-238 Gordianus I and Gordianus II assume emperorship of North Africa 238-244 Gordianus III emperor 241-271 Sapor I, King of Persia 242-243 Victorious campaigns against the Persians; battles of Resenae, Carrhae, and Nisibis 244-249 Philippus Arabs emperor and his son co-regent 247-249 248 Celebration of millenium of Rome 248-251 Decius emperor 250 Persecution of Christians 251 Decius and his son Herennius Etruscus fall in battle in Abrittus against Goths 251-153 Treborianus Gallus emperor 253 June-September, Aemilianus emperor 253-260 Valerian and his son Gallienus co-emperors, while Valerian campaigns in the East and Gallienus governs the West of the Empire 253 Persian War flares up again, Antioch lost to Persia 254-262 Revolts of Bagaudae, insurgent peasants, in Gaul and Spain 257-260 Persecution of Christian by Valerian 260 Valerian taken prisoner by Persians at Edesa 260-268 Gallienus sole emperor 260 Gallienus extends tolerance to Christians 260-272 Queen Zenobia of Palmyra seizes large areas of Asia Minor, Syria, and Egypt and sets up an independant empire until defeated and taken prisoner by Aurelian 261-274 Separatist empire set up in Gaul by Postumus (261-268) and Tetricus (270-274) 268-270 Claudius II Gothicus emperor 270-275 Aurelian emperor 276-282 Probus emperor 282-283 Carus emperor 282-285 Carinus at first co-emperor with Carus and then sole emperor 283 Persian campaign of Carus 284-305 Diocletian and Maximian co-emperors 293 Diocletian creates tetrarchy with himself and Maximian as co-Augusti in the East and West, and Galerius and Constantius Chlorus as co-Caesars 297 The Empire is divided administratively into twelve dioceses, each ruled by a vicarius 301 The Edict of Maximum Prices imposed throughout the Empire 303 Diocletian persecutes the Christians 305 Diocletian abdicates and forces Maximian to do likewise. Galerius and Constantius Chlorus co-Augusti 306 Constantine declared co-Augustus after death of his father Constantius Chlorus, but Galerius recognizes the Illyrian Severus in that rank and confers the title of Caesar on Constantine 306 Maxentius, son of Maximian, hailed as legitimate successor by the Praetorian Guard and the city of Rome; heads revolt against Constantine. His father comes out of retirement to profit from the situation, first on one side, then on the other 308 At an imperial conference of Diocletian, Galerius and Maximian at Carnuntum Licinius is declared Augustus of teh West, setting off an armed conflict between all rival contenders 310 Maximius Daia, nephew of Galerius, assumes on his own initiative the title of Augustus 311 An edict of tolerance for Christians issued by Galerius shortly before his death 312 Constantine's victory over Maxentius in battle at the Milvian Bridge puts Rome in his hands 313 Victory of Licinius over Maximinus Daia at the Hellespont is followed by reconciliation of the two victors 313 The co-emperors issue the Edict of Milan ending persecution of Christians 314 Armed conflict breaks out between the co-emperors: truces, claims, counterclaims, and wars follow for ten years with Constantine increasingly victorious 324 Constantine sole emperor after final defeat, abdication, and execution of Licinius 325 The Council of Nicaea formulates Nicene Creed and makes Christianity the religion of the Empire 326 Constantine chooses Byzantium as the new capital of the Empire and renames it Constantinopolis 337 May 22, death of Constantine the Great