Constantius I vs Tuoba Gui

Constantius I led an invasion to reclaim Britain from the usurper Allectus, who had succeeded Carausius. His forces landed near London and defeated Allectus, restoring Britain to the Roman Empire and ending the breakaway Britannic Empire.

Constantius I defeated the Alemanni at the Battle of Lingones (modern Langres) and later at Vindonissa. These victories secured the Rhine frontier and earned him the title Germanicus Maximus, strengthening his reputation as a capable military commander.

Upon the abdication of Diocletian and Maximian, Constantius I became the senior Augustus of the Western Roman Empire as part of the Tetrarchy. He ruled jointly with Galerius in the East, but his reign was short-lived as he died the following year.

Constantius I died at Eboracum (modern York) while on campaign against the Picts in northern Britain. His son Constantine was proclaimed Augustus by the troops, setting the stage for Constantine's eventual rise to sole emperor.

Constantius I, unlike his co-emperor Galerius, was tolerant of Christians and did not enforce the Diocletianic persecution in his territories. This policy of religious tolerance foreshadowed the Edict of Milan issued by his son Constantine.

Tuoba Gui declared himself Prince of Dai, later Emperor Daowu of Northern Wei, founding the Northern Wei dynasty. He united the Tuoba Xianbei tribes and established a capital at Shengle (modern Inner Mongolia), beginning a dynasty that would rule northern China for nearly 150 years.

Tuoba Gui defeated the Later Yan army at the Battle of Canhe Slope. The victory was decisive, with massive casualties on the Later Yan side. This battle broke the power of Later Yan and allowed Northern Wei to expand into central Hebei.

Tuoba Gui captured the Later Yan capital of Zhongshan (modern Dingzhou, Hebei). He annexed the Later Yan territories and moved the Northern Wei capital to Pingcheng (modern Datong), establishing a strong base for further conquests.

Tuoba Gui introduced the 'equal-field' (juntian) land system, distributing land to peasants based on the number of able-bodied laborers. This reform increased agricultural productivity, stabilized tax revenues, and reduced the power of landed aristocrats.

Tuoba Gui was assassinated by his son Tuoba Shao in a palace coup. The assassination stemmed from Tuoba Gui's increasingly erratic and paranoid behavior in his later years. His death led to a succession crisis, but his son Tuoba Si eventually took the throne.