阳木狗年 (male Wood-Dog) 501 or 120 or −652 — to — 阴木猪年 (female Wood-Pig) 502 or 121 or −651
Year 375 (CCCLXXV) was a common year starting on Thursday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year after the Consulship of Augustus and Equitius (or, less frequently, year 1128 Ab urbe condita). The denomination 375 for this year has been used since the early medieval period, when the Anno Dominicalendar era became the prevalent method in Europe for naming years.
The Quadi accept an uneasy peace from Merobaudes (Magister militum), which gives them land to settle on the Danube.
Gratian, age 16, takes over the government at Augusta Treverorum (modern Trier), but ministers wishing to retain the loyalty of the Illyrian army fear a usurper. They proclaim Valentinian's 4-year-old son Valentinian II co-emperor with his mother, Justina, as regent. Gratian reserves for himself the administration of the Gallic provinces, and hands over Italy, Illyrium, Hispania and Africa to his stepmother, who makes Mediolanum (Milan) her residence.
Gratian, advised by his chief advisor Ambrosius, begins a systematic persecution of the pagans. He confiscates the fortunes of the temples and adds the money to the Imperial Treasury. He proscribes Arianism and Donatism.
In Africa, the dissident Berber prince Firmus is delivered to the Romans by his brother Gildon.