Technology & Infrastructure in the 4th century

15 sourced entries, 300 CE to 386 CE, oldest first. Also see Technology & Infrastructure across every century or everything else in the 4th century.

• 300Diocletian's Palace, Split, Croatia, is built. Its model is nowadays kept at the Museo della Civilta Romana, Rome.source
• 300Wootz steel is developed in India (approximate date).source
• 303In Mexico, the civilization of Teotihuacan flourishes.source
• 308Constantine raids the territory of the Bructeri and builds a bridge across the Rhine at Cologne.source
• 308Bereft of his father's support, Maxentius increasingly presents himself as the Conservator Urbis Suae (Preserver of His Own City). Construction of the Basilica of Maxentius (or Basilica Nova), the largest building in the Roman Forum, is begun.source
• 315July 25 – The Arch of Constantine is completed near the Colosseum at Rome to commemorate Constantine's victory over Maxentius at the Milvian Bridge. As part of the ceremony Constantine is expected to make a sacrifice to Rome's traditional gods, but he refuses to do so.source
• 315Immense baths are constructed in Augusta Treverorum (modern-day Trier).source
• 317The earliest historically verified reference to tea is recorded, although the Chinese have been drinking the beverage for centuries.source
• 322The first dependable representation of a horse rider with paired stirrups is found in China, in a Jin Dynasty tomb.source
• 328July 5 – Constantine's Bridge, built over the Danube between Sucidava (Corabia, Romania) and Oescus (Gigen, Bulgaria), is officially opened by the Roman architect Theophilus Patricius.source
• 332Constantine I continues construction of a bridge (in imitation of Trajan and his architect Apollodorus of Damascus) across the Danube, for forward-staging grounds for planned campaigns against local tribes.source
• 355January 1 – Arbitio and Lollianus Mavortius begin their term as Roman consuls.source
• 359The first known Prefect of the city of Constantinople, Honoratus, takes office.source
• 366Valens builds a pontoon bridge across the Danube, and drives the Visigoths further north, where they will come under pressure from the advancing Huns.source
• 386Theodosius I begins to rebuild the present-day Basilica of Saint Paul Outside the Walls.source