On This Day

Constantine I is proclaimed Roman Emperor by his troops

Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to...

Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a pivotal role in elevating the status of Christianity in Rome, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire.

Historical Significance

Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity.

Key People

Constantine the Great

Roman emperor from 306 to 337

Roman emperor from 306 to 337

Events Before

  1. St Gaius ends his reign as Catholic Pope

    St Gaius ends his reign as Catholic Pope

  2. St Marcellinus begins his reign as Catholic Pope

    The pope is the bishop of Rome and the head of the worldwide Catholic Church. He is also known as the supreme pontiff, Roman pontiff, or sovereign pontiff.

  3. San Marino, one of the smallest nations in the world and the world's oldest republic still in existence, is founded by S

    San Marino, one of the smallest nations in the world and the world's oldest republic still in existence, is founded by Saint Marinus

  4. First official Roman edict for persecution of Christians issued by Emperor Diocletian at Nicomedia, ordering all churche

    First official Roman edict for persecution of Christians issued by Emperor Diocletian at Nicomedia, ordering all churches to be closed and scriptures burnt

  5. On a voyage preaching the gospel, Saint Fermin of Pamplona is beheaded in Amiens, France

    On a voyage preaching the gospel, Saint Fermin of Pamplona is beheaded in Amiens, France

Events After

  1. Roman Emperor Constantine I marries Fausta, daughter of the Emperor Maximian, later murdering her in 326

    Roman Emperor Constantine I marries Fausta, daughter of the Emperor Maximian, later murdering her in 326

  2. Marcellus I begins his reign as Catholic Pope, serving until his death in 309

    Marcellus I begins his reign as Catholic Pope, serving until his death in 309

  3. St. Eusebius begins his reign as Catholic Pope

    St. Eusebius begins his reign as Catholic Pope

  4. St. Eusebius ends his reign as Catholic Pope

    St. Eusebius ends his reign as Catholic Pope

  5. Roman Emperor Galerius issues the Edict of Toleration, ending the persecution of Christians in the Roman Empire

    Early Christians were heavily persecuted throughout the Roman Empire until the 3rd century.

More from the 300s

Frequently Asked Questions

What happened on July 25, 306?
Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity. He played a pivotal role in elevating the status of Christianity in Rome, the Edict of Milan decriminalising Christian practice and ceasing Christian persecution. This was a turning point in the Christianisation of the Roman Empire.
Why is Constantine I is proclaimed Roman Emperor by his troops significant?
Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to Christianity.
Who was involved in Constantine I is proclaimed Roman Emperor by his troops?
Key figures include Constantine the Great (Roman emperor from 306 to 337).

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