131 christians everyone should know: rulers

Constantine (First Christian Emperor)

• Who he was: Roman emperor from A.D. 306–337.

• What he did: Became the first Roman emperor to convert to Christianity and legalized the faith with the Edict of Milan (313).

• Why he mattered: His conversion transformed Christianity from a persecuted religion into one favored by the state, setting the stage for its spread across the Roman Empire.

Theodosius I (Emperor Who Made Christianity “the” Roman Religion)

• Who he was: Roman emperor from 379–395.

• What he did: Declared Christianity the official state religion of the Roman Empire and banned pagan worship.

• Why he mattered: He solidified Christianity’s dominance in the West, ensuring it would shape European civilization for centuries.

Justinian I and Theodora I (Greatest Byzantine Rulers)

• Who they were: Byzantine emperor (527–565) and his wife, empress Theodora.

• What they did: Strengthened the Byzantine Empire, codified Roman law (Justinian Code), built the Hagia Sophia, and supported the church. Theodora was a powerful co-ruler who influenced social reforms, including women’s rights.

• Why they mattered: They preserved and shaped Christian Roman heritage and left a lasting legacy on law, architecture, and theology.

Leo I (Pope and International Diplomat)

• Who he was: Pope from 440–461, also known as Leo the Great.

• What he did: Defended Rome from invasion (famously persuaded Attila the Hun to turn back) and clarified Christian doctrine on Christ’s nature at the Council of Chalcedon.

• Why he mattered: He established the pope as a spiritual leader with international influence and defined key Christian beliefs.

Gregory the Great (“Servant of the Servants of God”)

• Who he was: Pope from 590–604.

• What he did: Reorganized church leadership, strengthened missionary work (notably sending Augustine to England), and modeled humble yet powerful papal service.

• Why he mattered: He shaped the medieval papacy, expanded the church’s reach, and emphasized pastoral care and service.

Charlemagne (Christian Ruler of a “Holy” Empire)

• Who he was: King of the Franks and Lombards; crowned Holy Roman Emperor in 800.

• What he did: United much of Western Europe under Christian rule, promoted education and church reform, and linked the church with political power.

• Why he mattered: He laid the foundation for Christian Europe and the idea of a unified “Holy Roman Empire.”

Innocent III (Warring “Vicar of Christ”)

• Who he was: Pope from 1198–1216.

• What he did: Asserted papal authority over kings, called crusades (including the Fourth Crusade), and influenced major European rulers.

• Why he mattered: He represented the height of papal political power, but his aggressive policies also led to conflict and division.

Louis IX (Saintly King of France)

• Who he was: King of France (reigned 1226–1270), later canonized as Saint Louis.

• What he did: Known for piety, justice, and charity; led two crusades; built Sainte-Chapelle; and ruled with fairness and devotion.

• Why he mattered: He became the model of a Christian monarch—righteous, charitable, and deeply faithful.

Henry VIII (Defender of the Faith)

• Who he was: King of England (reigned 1509–1547).

• What he did: Initially defended Catholicism against Protestant reformers (earning the title “Defender of the Faith”), but later broke from the Catholic Church to form the Church of England.

• Why he mattered: His break with Rome began the English Reformation, changing the religious and political landscape of England permanently.