325 CE
Crown Prince Cheng of Jin, age 4, succeeds his father Ming of Jin as emperor of the Eastern Jin dynasty. During his reign, he is largely advised by regents, his uncle Yu Liang and high-level officials. First Council of Nicaea: Constantine summons an ecumenical council of bishops in Nicaea (Turkey). The Nicene Creed, adopted on June 19, declares that the members of the Trinity (the Father, the Son, and the Holy Spirit) are equal. The council decides that Easter is celebrated on the first Sunday after the first full moon after the vernal equinox. Arius is exiled to Illyria; his works are confiscated and consigned to the flames. German and Sarmatian campaigns of Constantine: Emperor Constantine I personally assures the security of the Danube frontier by defeating the Goths, the Vandals and the Sarmatians.
Geopolitics & Diplomacy
- German and Sarmatian campaigns of Constantine: Emperor Constantine I personally assures the security of the Danube frontier by defeating the Goths, the Vandals and the Sarmatians.source
Conflict & Security
Religion & Belief
- May 20 – First Council of Nicaea: Constantine summons an ecumenical council of bishops in Nicaea (Turkey). The Nicene Creed, adopted on June 19, declares that the members of the Trinity (the Father, the Son, and the Holy Spirit) are equal. The council decides that Easter is celebrated on the first Sunday after the first full moon after the vernal equinox. Arius is exiled to Illyria; his works are confiscated and consigned to the flames.source
- The Colossus of Constantine in the Basilica of Maxentius and Constantine, Rome, is perhaps remodelled at about this date. (The remains are moved to the Palazzo dei Conservatori, Rome, in the 15th century).source
Health & Medicine
- April 1 – Crown Prince Cheng of Jin, age 4, succeeds his father Ming of Jin as emperor of the Eastern Jin dynasty. During his reign, he is largely advised by regents, his uncle Yu Liang and high-level officials.source
Births
- Wang Meng (or Jinglüe), Chinese prime minister (d. 375)source
Deaths
- October 18 – Ming of Jin, Chinese emperor (b. 299)source
- Martinian, deposed Roman emperor (executed)source
- Licinius, deposed Roman emperor (executed)source
- Tuoba Heru, Chinese prince of the Tuoba Daisource
- Approximate date – Iamblichus, Syrian philosopher and writer (b. 245)source
- c. July – Li Ju (or Shihui), Chinese general and warlordsource