Diocletian, in an attempt to prevent counterfeiting,…

 Emperor Hui’s regent Sima Jiong, the fourth of the eight princes commonly associated with the War of the Eight Princes, responds to Sima Yun’s usurpation by leading a coalition of forces, including Sima Ying and Sima Yong, against Sima Lun.

In 301, they defeat Sima Lun's troops, kill him, and then reestablish Emperor Hui as the emperor, with Sima Jiong exerting the most influence at the imperial court.

Armenian monarch Tiridates III, who owes his throne to the Roman Empire, adopts Christianity in 301 as his nation’s official religion, making Armenia the first Christian state.

The king appoints Gregory the Illuminator, who had been the instrument of his conversion, as the first Catholicos of the Armenian Apostolic Church.

San Marino was founded, according to tradition, in 301 after a Christian stonemason named Marinus the Dalmatian, later venerated as Saint Marinus, emigrated in 257 from the Dalmatian island of Rab, then a Roman colony, when the emperor Diocletian issued a decree calling for the reconstruction of the city walls of Rimini which had been destroyed by Liburnian pirates.

Finding persecution of his Christian beliefs, Marinus hid on the peak of Mount Titano (the highest of San Marino's seven hills) and founded a small community following Christian beliefs.

The owner of the land, Felicissima, a sympathetic lady of Rimini, bequeathed it to the small Christian community of mountain dwellers, recommending to them to remain always united.

It is certain that the region has been inhabited since prehistoric times, although evidence of the existence of a community on Mount Titano dates back only to the Middle Ages.

That evidence comes from a monk named Eugippio, who reports in several documents going back to 511 that another monk lived here.

In memory of the stonecutter, the land was renamed "Land of San Marino", and was finally changed to its present-day name, "Republic of San Marino", the world's fifth-smallest state, which claims to be world's oldest republic.

Porphyry, the chief disciple, critic, promoter, and biographer of the late Neoplatonist philosopher Plotinus, publishes his master’s fifty-four essays posthumously in 301, arranging them in 6 sections of 9 essays each, calling them the Enneads (“The Nines”).

Influenced by Pythagorean, Peripatetic, and Stoic ideas, the Enneads defend Plato and Platonism against the criticisms of Aristotle, but in so doing embrace a number of Aristotle's own concepts.

Plotinus repeatedly demonstrates the inadequacy of Aristotle's categories and logic to account for the whole of reality—both the things known by the senses and those known by the intellect.

Plotinus agrees with the skeptics that knowledge is essential in comprehending the Platonic forms that are "beyond" the physical heavens.

He argues, however, that, as humans possess knowledge, souls must somehow acquire it by journeying to this "transcelestial" place to see the forms there.

Sima Jiong tries to centralize power in his hands but the princes rebel against him: he is defeated by Sima Ai, the Prince of Changsha, and killed in 302.

Sima Ai, the fifth of the eight princes, becomes the effective regent, but in order to reduce opposition, he submits all important matters to Sima Ying, still stationed at Yecheng.

Narseh rules Persia until his death in 302; he is succeeded by Hormizd (Hormuz) II.

Maximian had returned to the north of Italy after his Mauretanian campaign, living a life of leisure in palaces in Milan and Aquilea, and leaving warfare to his subordinate Constantius.

Maximian is more aggressive in his relationship with the Senate than Constantius, and Lactantius contends that he terrorized senators, to the point of falsely charging and subsequently executing several, including the prefect of Rome in 301/2.

Constantius, in contrast to Maximian, maintains good relations with the senatorial aristocracy and spends his time in active defense of the empire.

He had taken up arms against the Franks in 300 or 301 and in 302—while Maximian is resting in Italy—continues to campaign against Germanic tribes on the Upper Rhine.

Sima Ai, as regent, pays attention to reforming the government, and he sees the importance of formally honoring Emperor Hui while maintaining resemblance to impartial governance.

He continues to try to share power with Sima Ying.

However, in autumn 303, Sima Yong, dissatisfied that his plan had not come to fruition, persuades Sima Ying to again join him against Sima Ai.

While Sima Yong and Sima Ying have overwhelming force, their forces cannot score a conclusive victory against Sima Ai.

Chinese poet Lu Ji leads a Taoist and Buddhist-influenced movement toward a more individualistic and uninhibited literary style.

After Wu’s subjugation by the Jin Dynasty in 280, Lu Ji, a direct descendant of the founders of Eastern Wu and son of the general Lu Kang, had moved with his brother Lu Yun to the capital, Luoyang, where he has become prominent in both literature and politics and has been made president of the imperial university.

According to Achilles Fang, quoted in Eliot Weinberger (ed.

), The New Directions Anthology of Classical Chinese Poetry (New Directions, 2003: ISBN 0811215407), p. 240, “ He was too scintillating for the comfort of his jealous contemporaries; in 303 he, along with his two brothers and two sons, was put to death on a false charge of high treason."

Lu Ji wrote much lyric poetry but is better known for writing fu, a mixture of prose and poetry.

He is best remembered for the Wenfu ("On Literature"), a piece of literary criticism that discourses on the principles of composition.

Diocletian's preference for activist government, combined with his self-image as a restorer of past Roman glory, presages the most pervasive persecution of Christians in Roman history.