303 ADGalerius Convinces Diocletian To Persecute Christians- Galeria the Roman Augustus convinced Diocletian to begin a general persecution of Christians in an attempt to stop the growth of the religion. Churches were burned, and clergy were imprisoned. Persecution decreased in the Western Empire by 305 A.D. and ended in the East in 313 A.D.
317 ADTatar Warriors Break Through Great Wall- Tatar warriors broke through the Great Wall of China that had been built during the Han Dynasty to provide Northern China with protection against invasion. The Tatars drove out the Western Chin Dynasty, which was forced to move its capital to Nanking.
320 ADGupta Dynasty- The Gupta Empire was founded in 320 by Chandragupta I. Under his successor, Samudragupta, the Gupta Empire was extended to include all of Northern India. The Gupta Empire ushered in a new golden age of Indian culture.
324 ADConstantine The Great & The Battle Of Adrianople - Constantine the Great, who was named Caesar by his troops in Britain in 312 A.D., initiated a civil war of succession against his potential rivals for the throne. In a series of engagements that culminated in 324 A.D. at the Battle of Adrianople (in today's Turkey), Constantine defeated all his rivals and became the undisputed emperor of all Rome.
325 ADPersian Repel Arabs - Persia was invaded by Arabs from Baharian and Mesopotamia. Shapur II became leader of the Persians. It was he who carried the war to the Arabs, seizing much of Arabia and making them vassal states to the Persian Empire.
330 ADConstantine The Great Establishes His Capital At Byzantium- In 330 Constantine the Great dedicated his new capital at Byzantium. The city that became known as Constantinople. It was strategically located in the East dominating the Bosphorus Straits. Constantine spent four years building his new capital.
337 ADConstantine The Great Dies And Empire Divides- In 337 A.D., Constantine died. He left his empire to his sons. The empire soon found itself divided with the Western Roman Empire governed from Rome by Constans and the Eastern Roman Empire governed by Constantius II.
351 ADBattle At Mursa- Reunites Empire- At the Battle of Mursa in present-day Croatia, Constantius defeated Magnentius. Magnentius committed suicide and the Roman Empire was once again united.
361 - 363 ADBattle Of Argentoratum- At the Battle of Argentoratum in 357 A.D., the Roman general Julian drove the Franks from Gaul, thus re-establishing the Rhine as the frontier of the Empire. Julian's victory served to ensure his popularity and he became the next Roman Emperor. But his reign lasted only 18 months: from November 361 to June 363 A.D. Julian is best known for his attempt to reinstitute paganism into Rome.
376 AD Ostrogoths Subjected By The Huns- The Huns, a nomadic Mongol people, swept in from Asia. They managed to defeat the Ostrogoth Empire. This brought to an end an empire that had dominated Eastern Europe for 200 years.
378 ADValens Killed by Visigoths- After their defeat by the Huns, the Visigoths sought refuge in the Roman Empire. The Roman emperor Valens gave them permission to cross the Danube as long as they agreed to disarmament. In the end, the Visigoths were mistreated by Roman officials and they revolted. At the Battle at Adrianople, the Visigoths deployed mounted cavalry against the Romans. The Romans were soundly defeated by the Visigoths and Valens was killed. This represented one of the worst defeats ever suffered by the Romans. The northern borders of the Empire had been permanently pierced.
395 ADTheodosius Dies Empire Split Permantly- When Emperor Theodosius died in 395 A.D., the Roman Empire was forever split. Theodosius was succeeded by his sons Arcadius, who ruled the Eastern portion, and Honorius, who ruled the Western.