311, written in Roman numerals as CCXI, was a common year beginning on Monday under the Julian calendar. It sits in the period commonly called the Late Antiquity, a time of political realignment across the Roman world and of dramatic upheaval on China's northern frontiers. The year is remembered for events that affected the legal status of Christianity in the Roman Empire and for the collapse of one of the Jin dynasty's key cities in China.

Major events

Several developments in 311 had long-term consequences for religion and imperial power structures:

  • In the Roman East, the emperor Galerius issued an edict that ended official persecution of Christians in territories under his control. This gesture recognized the growing presence of Christianity and allowed its followers to practice their faith without state-sanctioned penalties.
  • Political instability continued within the Tetrarchy-era arrangements, as rival claimants and regional rulers maneuvered for advantage. The year saw shifting alliances that would culminate in further contests for supremacy in the 310s.
  • In northern China, forces of the Xiongnu-led state of Han-Zhao captured the Jin capital Luoyang. This sack—often called the Disaster of Yongjia—severely weakened the Western Jin dynasty and contributed to a prolonged period of division and migration in China.

Significance and context

The edict in the Roman East is an important milestone in the gradual transition from occasional persecution to imperial tolerance and eventual favor for Christianity. Although not yet a state religion, the legal reprieve helped Christians organize more openly. In China, the fall of Luoyang marked a turning point: the loss of the central capital precipitated further fragmentation of northern China and large population movements southward that reshaped Chinese political geography for decades.

Notable figures and outcomes

  • Galerius — Roman emperor in the Balkans and the initiator of the edict ending persecutions in his territories; he died later in 311, accelerating political change.
  • Ruling families of the Jin dynasty — suffered decisive military setbacks with the loss of Luoyang, undermining imperial authority and opening the way for successive regimes in the north.

Beyond immediate politics, the year 311 illustrates the interconnected nature of late antique transformations: legal reforms in the Roman world and military collapses in East Asia each contributed to longer trajectories of religious, social, and demographic change. For chronological reference, 311 is often cited by historians when tracing the decline of Roman persecution of Christians and the early stages of China’s Sixteen Kingdoms period.