Geopolitics & Diplomacy in the 3rd century

90 sourced entries, 200 CE to 299 CE, oldest first. Also see Geopolitics & Diplomacy across every century or everything else in the 3rd century.

• 200The province of Numidia is taken from the African proconsul, and made an Imperial province.source
• 200Rudrasena I, Saka ruler of the Western Satrap dynasty, becomes king of Malwa in Classical India.source
• 201Lucius Annius Fabianus and Marcus Nonius Arrius Mucianus become Roman Consuls.source
• 203Emperor Septimius Severus rebuilds Byzantium, and expands the southern frontier of Africa, with the metropolis Carthage re-fortified.source
• 203Gaius Fulvius Plautianus and Publius Septimius Geta become Roman Consuls.source
• 204Lucius Fabius Cilo and Marcus Annius Flavius Libo become Roman Consuls.source
• 205Marcus Aurelius Antoninus Augustus and his brother Publius Septimius Geta Caesar become Roman Consuls.source
• 205Hadrian's Wall is restored, after heavy raids by Caledonian tribes had overrun much of northern Britain.source
• 208Marcus Aurelius Antoninus Augustus and his brother Publius Septimius Geta Caesar become Roman consuls.source
• 212Edessa in Mesopotamia becomes a Roman province.source
• 212The edict of Emperor Caracalla (Constitutio Antoniniana) extends Roman citizenship to all free inhabitants of the Roman Empire, with the exception of a limited group that may include Egyptians. The Jewish people are among those who receive citizenship. All free women in the Empire are given the same rights as Roman women.source
• 213Cao Cao, the prime minister of the Han dynasty, is titled Wei Gong (Duke of Wei) and given a fief of ten cities under his domain. This later becomes the Kingdom of Wei.source
• 213Emperor Caracalla leaves Rome and expels some Germanic marauders from Gaul, while his mother, Julia Domna, rules the Empire. He defends the northern Rhine frontier against the Alamanni and the Chatti. Caracalla wins over the Germanic tribes on the banks of the River Main, and gives himself the title "Germanicus". It is probably while campaigning in Germania that he takes a liking to the caracalla, a Celtic or Germanic tunic from which he acquires the name by which he is known.source
• 214The kingdom of Osroene becomes a province of the Roman Empire.source
• 214Liu Bei takes Yi Province from his clansman Liu Zhang, forming the later basis for Shu Han during the Three Kingdoms period.source
• 215Vachagan I becomes king of Caucasian Albania.source
• 219Imperator Marcus Aurelius Antoninus Augustus (Elagabalus) and Quintus Tineius Sacerdos become Roman Consuls.source
• 220December 11 – Cao Pi receives the abdication of Emperor Xian of Han and proclaims himself emperor of Cao Wei. This ends the Han dynasty, the former emperor being created Duke of Shanyang.source
• 220Imperator Marcus Aurelius Antoninus Augustus (Elagabalus) and Publius Valerius Comazon become Roman consuls.source
• 221May 15 – Liu Bei, Chinese warlord and descendant of the imperial clan of the Han dynasty, proclaims himself emperor in Chengdu, Sichuan, and establishes the state of Shu Han.source
• 222Alexander Severus succeeds Elagabalus. He is only 13 years old; his mother, Julia Avita Mamaea, governs the Roman Empire with the help of Domitius Ulpianus and a council composed of 16 senators.source
• 224January 1 – Gaius Bellicius Torquatus and Appius Claudius Julianus II begin their one year terms as the new Roman consuls.source
• 227The rule of High King Cormac mac Airt begins (approximate).source
• 227King Ardashir I annexes his new empire from the east to the northwest. He conquers, with his army, the provinces of Chorasmia, Sistan and the island Bahrain in the Persian Gulf. The kings of the Kushan Empire and Turan recognize Ardashir as their overlord.source
• 227Dongcheon becomes ruler over the Korean kingdom of Goguryeo.source
• 229June 23 – Chinese warlord Sun Quan formally declares himself emperor of the Eastern Wu state. The city of Jianye (modern Nanjing) is founded as the capital of Eastern Wu. The independent kingdoms in Cambodia and Laos become Eastern Wu vassals.source
• 229Emperor Alexander Severus and Dio Cassius are joint Consuls.source
• 230Emperor Alexander Severus decides that Thessaly should be a separate province from Macedonia. He increases taxes, in order to maintain the war against the Sassanids, and strengthen the defenses of the Roman Empire.source
• 230Jobun becomes king of the Korean kingdom of Silla.source
• 231Origen, disciple of Ammonius Saccas, founder of Neoplatonism, is exiled in Caesarea.source
• 236Emperor Maximinus Thrax and Marcus Pupienus Africanus Maximus become Roman consuls.source
• 238Future Emperor Valerian becomes princeps senatus.source
• 239Cao Fang succeeds his adoptive father Cao Rui as emperor of the Cao Wei state, in the Three Kingdoms period of China.source
• 240Maharaja Sri-Gupta becomes ruler of the Gupta Empire (approximate date).source
• 241Prince Shapur I succeeds his father Ardashir I as ruler of the Sassanid Empire. He begins his expansion in India.source
• 241Gaius Furius Sabinius Aquila Timesitheus becomes praetorian prefect and de facto ruler of the Roman Empire.source
• 247Cheomhae becomes king of the Korean kingdom of Silla.source
• 247Marcus Julius Philippus Augustus and his 10-year-old son Marcus Julius Philippus Caesar become Roman Consuls.source
• 248Jungcheon becomes ruler of the Korean kingdom of Goguryeo (until 270).source
• 248The revolts of Pacatianus in Moesia and Iotapianus in Syria are put down by Senator Trajan Decius, by order of Emperor Philip the Arab.source
• 249Trajan Decius puts down a revolt in Moesia and Pannonia. Loyal legionaries proclaim him emperor, and he leads them into Italy.source
• 251Sima Shi, Sima Yi's eldest son, inherits his father's authority.source
• 251Gallus makes peace with the Goths; he permits them to keep their plunder, and offers them a bribe not to return.source
• 252Sun Liang succeeds his father Sun Quan, as emperor of the Chinese state of Eastern Wu.source
• 257Emperor Gallienus brings some order to the Danube area.source
• 257Valerian, under guardianship of Ingenuus, is established at Sirmium (Pannonia) to represent the Roman government in the troubled Illyrian provinces.source
• 259Postumus revolts against Gallienus in Gaul. The western provinces of Britain and Spain join his independent realm—which is called in modern times the Gallic Empire.source
• 260Gallienus establishes himself at Mediolanum (modern Milan); he reorganizes the army, supported by elite cavalry, and dispatches troops to the Rhine frontier.source
• 260Gallienus becomes the sole emperor of Rome; during his reign the Pannonian governor Ingenuus revolts on the Danube.source
• 260The Franks take control over the Scheldt estuary (approximate date).source
• 260Postumus executes Saloninus and his adviser Silvanus after breaching the walls of Cologne. He is recognized as emperor and establishes his capital at Trier.source
• 260Postumus wins over all the Roman provinces west of the Alps, including Gaul, Britain and Hispania.source
• 260Saloninus, son of Gallienus, is proclaimed Augustus by his troops. Postumus besieges Cologne, where Silvanus is praetorian prefect and Roman ruler of Gaul.source
• 261Michu of Silla ascends to the Korean throne of Silla, becoming the first ruler of the Long Kim line.source
• 263King Odenathus of Palmyra declares himself ruler of the area west of the River Euphrates and is declared Dux Orientalis by the Roman emperor Gallienus.source
• 263Sima Zhao, regent of the Cao Wei state, receives and accepts the nine bestowments, state chancellorship, and the title Duke of Jin from Cao Huan.source
• 264Sun Hao succeeds Sun Xiu as emperor of the Chinese state of Eastern Wu.source
• 265Sima Zhao, who had been the regent and de facto primary authority of the state of Cao Wei for little over 10 years by this point, passes away, leaving his authority to his eldest son, Sima Yan, who will go on to disestablish the state of Cao Wei in February 266, founding the Jin dynasty.source
• 266February 4 – Sima Yan, regent of the Chinese state of Cao Wei, forces the last Cao Wei emperor Cao Huan to abdicate in his favour. The Cao Wei state's existence comes to an end. Sima Yan establishes the Jin Dynasty, and becomes its first emperor on 8 February, and is historically known as "Wu of Jin". He establishes his capital at Luoyang, and gives his male relatives independent military commands throughout his empire.source
• 266The rule of High King Cormac mac Airt ends (approximate date).source
• 268The Visigoths first appear as distinct people.source
• 270Seocheon becomes ruler of the Korean kingdom of Goguryeo.source
• 271Aurelian withdraws Rome's administrative and military presence from Dacia (modern Romania), thereby rationalizing the Danube frontier and freeing resources for the forthcoming campaign against Zenobia.source
• 275The Pallava dynasty begins in Southern India.source
• 276Probus returns the aurelianianus to the tariffing of Aurelian.source
• 277Probus enters Rome, to have his position as Emperor ratified by the Senate.source
• 278Probus resettles the Germanic tribes in the devastated provinces of the Roman Empire. He adopts the titles of Gothicus Maximus and Germanicus Maximus.source
• 280King Bahram II of the Sassanid Empire (Persia) sends envoys to seek peaceful relations with Rome.source
• 280The Germans destroy the Roman fleet on the Rhine; Bonosus is proclaimed emperor at Colonia Agrippina (Cologne).source
• 280Emperor Probus drives the Alans off to Asia Minor and suppresses the revolt in Gaul; Proculus is executed.source
• 280Emperor Wu of the Jin dynasty completes the unification of China, which was previously divided between three contending powers during the Three Kingdoms period. The Jin dynasty's capital of Luoyang becomes a thriving centre of commerce as foreign diplomats and traders travel there.source
• 281Tiberianus served his first of two terms as Consul.source
• 282Carus defeats the Quadi and Sarmatians on the Danube; for his victories he is given the title Germanicus Maximus.source
• 283The corrector Aurelius Julianus usurps power in Pannonia but is defeated by Carinus.source
• 283Carinus campaigns with success in Britain and on the Rhine frontier.source
• 283Spring: Emperor Carus makes his son Carinus the Augustus in the west.source
• 284Yurye becomes king of the Korean kingdom of Silla.source
• 286April 1 – Diocletian rewards Maximian by elevating him to co-emperor, giving him the title Augustus.source
• 287Diocletian signs a peace treaty with King Bahram II of Persia, and installs the pro-Roman Arsacid Tiridates III as king over the western portion of Armenia.source
• 288Maximian makes an alliance with the Frankish king Gennobaudes.source
• 291An uneasy peace is established between the emperors Diocletian and Maximian on the one hand, and the rival emperor Carausius on the other.source
• 291Perhaps in cooperation with the forces of Maximian, Carausius campaigns successfully against Germanic raids in Gaul and Britain. Also during his reign, Carausius begins building the forts of the Saxon Shore.source
• 291Winter: The emperors Diocletian and Maximian convene in Milan.source
• 292Bongsang becomes ruler of the Korean kingdom of Goguryeo.source
• 293Constantius retakes some of the Gallic territories from the usurper Carausius. He conquers the crucial port of Bononia (modern Boulogne).source
• 294Tuoba Luguan succeeds his nephew Tuoba Fu, as chieftain of the Chinese Tuoba clan.source
• 295Tuoba Luguan divides the territory of the Tuoba clan into three areas. His nephews Tuoba Yilu and Tuoba Yituo become chieftains of the western and central areas of (Shanxi province). Tuoba Luguan dominates the eastern area (near Hohhot).source
• 298Girim becomes the king of the Korean kingdom of Silla.source
• 299Peace of Nisibis: Emperor Diocletian signs a treaty with the Persian king Narseh that will last for 40 years. The Persians accept Roman dominion over Armenia, the Caucasus, and Upper Mesopotamia. The pro-Roman ruler Tiridates III receives all of Armenia as far as the border with Atropatene. Mirian III of the Kingdom of Iberia is made a Roman client, and at some point in time, as a result of the treaty, Caucasian Albania will follow suit. Rome also gains five satrapies beyond the Tigris, which are perhaps given to Tiridates to administer.source
• 299To celebrate his victory over the Persians, Galerius commissions the Arch of Galerius in Thessaloniki (modern Greece).source