In the sixth century, under the emperor Justinian I, who ruled from 527 to 565, the eastern empire tried to restore the glory of Rome. Justinian's reign produced lasting achievements in law and architecture, a costly attempt to reconquer the West, and one of the deadliest pandemics in history. At his side stood one of the most remarkable women ever to share imperial power.

Theodora

Theodora began life far from the palace. Her father kept bears for the circus, and she worked as an actress, a profession then associated with prostitution. Roman law forbade senators from marrying actresses; Justinian had the law changed and married her around 525. When he became emperor, she was crowned empress. She was an influential adviser who championed laws protecting women, including measures against forced prostitution and in favor of women's property rights, and she sheltered religious dissenters whom her husband's church opposed.

Much of what we know about her comes from Procopius, the leading historian of Justinian's reign. In his official histories he praised the emperor. In a work kept secret during his lifetime, the Secret History, he attacked Justinian and Theodora savagely, describing her as monstrously immoral. Historians treat both his praise and his abuse with caution.

The Nika riots

Constantinople's public life centered on the Hippodrome, a huge stadium for chariot racing. Fans formed rival factions, named after their teams' colors, especially the Blues and the Greens, which were also political and social groups. In January 532, angered by the emperor's officials and taxes, the two factions joined forces in a revolt, shouting “Nika!” (“Conquer!”). Rioters burned much of the city center, including the great church of Hagia Sophia, and proclaimed a rival emperor.

Justinian prepared to flee. According to Procopius, Theodora spoke against flight, declaring that she would rather die an empress than live as a fugitive, and quoting an old saying that “royalty is a good burial shroud.” Justinian stayed. His generals, including Belisarius, trapped the rioters in the Hippodrome and massacred them; Procopius says about thirty thousand were killed.

Hagia Sophia

From the ruins, Justinian built his greatest monument. The new church of Hagia Sophia, “Holy Wisdom,” was built in less than six years, from 532 to 537, designed by two mathematicians and engineers, Anthemius of Tralles and Isidore of Miletus. Its enormous dome, over thirty meters across, seemed to float on a ring of windows, filling the interior with light. A later legend has Justinian exclaim on entering it that he had surpassed Solomon, builder of the Temple in Jerusalem. For nearly a thousand years it was the largest church in the Christian world.

The Code

Justinian's most lasting achievement was legal. Roman law had grown over a thousand years into a vast, contradictory mass of statutes and opinions. Justinian appointed a commission, led by the jurist Tribonian, to organize it. The result, completed between 529 and 534, is known as the Corpus Juris Civilis, the Body of Civil Law. It included a code of imperial laws, a digest of the opinions of classical jurists, and a textbook for students. Rediscovered in Western Europe centuries later, it became the foundation of the civil law systems used today in most of continental Europe, Latin America and many other places.

Reconquest and plague

Justinian sought to recover the western lands lost to Germanic kingdoms. Belisarius conquered the Vandal kingdom in North Africa in 533 to 534. The war to retake Italy from the Ostrogoths began in 535 and dragged on for nearly twenty years, devastating the peninsula. Imperial forces also took part of southern Spain.

In 541, a pandemic struck. The Plague of Justinian spread through the Mediterranean world; Procopius described thousands dying daily in Constantinople. Modern DNA analysis of victims' remains has confirmed it was caused by the same bacterium as the later Black Death. It returned in waves for two centuries, killing a large share of the population, weakening the empire's economy and army just as it was stretched to the limit.

Silk

Procopius also tells how, around the 550s, monks smuggled silkworm eggs from Central Asia to Constantinople hidden in hollow canes, allowing the empire to produce its own silk rather than buying it from Persian middlemen. Silk became a valuable state industry.

Worked example: judging Justinian

Weigh Justinian's reign as a historian would.

• Achievements. The Corpus Juris Civilis shaped legal systems used by billions of people. Hagia Sophia remains one of the world's great buildings. Territory was regained in Africa, Italy and Spain.
• Costs. The Nika massacre killed tens of thousands. The Italian war ruined Italy. Heavy taxes burdened the people. Religious policy persecuted dissenters, pagans and others.
• Bad luck. The plague, which no ruler could control, undermined his ambitions.
• Aftermath. Within a few decades of his death, much of Italy was lost to the Lombards, and the empire faced enemies in the east it could barely hold off.

A balanced verdict sees a ruler of vast ambition whose legal and architectural legacy outlasted his conquests by many centuries. It also shows that the achievements of rulers are often paid for by the lives of people whose names history does not record.