The Battle at Milvian Bridge
(312 AD)

Forces / Leaders:
~50,000 men under Constantine
~75,000 men under Maxentius

Saxa Rubra, Italy; near the Milvian Bridge on the bank of the Tiber River.

Constantine’s victory over Maxentius at the Milvian Bridge led directly to Christianity being the principal Religion of the Roman Empire, and ultimately of Europe.

Diocletian’s Tetrarchy. In the 49 years between 235 and 284 AD, twenty-six different emperors ruled the Roman Empire. Political chaos plagued the empire. At last, Diocletian seized and sustained power in 284 AD. As emperor, Diocletian spent most of his time preoccupied with reforming the empire, so as to stabilize it, thus avoiding any future flip-flopping of emperors – and ensuring his own political safety.

Diocletian knew that the Roman Empire, as it stood in 284 AD, was excessively vast (it stretched from current day Scotland to Iraq) for one man to effectively rule it all. His main reform pertained to the ruling of the empire. Diocletian proposed a rule by four men over four different regions, a tetrarchy. The four regions included:

- The Prefecture of Gaul (Western Europe and the northern part of present day Morocco)

- The Prefecture of Italy (The Alps, Italy, the Northern Balkans, and Northern Africa)

- The Prefecture of Illyricum (Greece, Macedonia, and Crete)

- The Prefecture of the East (Everything East from present day Turkey and Egypt)

Diocletian named a co-emperor of Maximian, who would rule the Prefecture of Italy from Rome, while Diocletian ruled the Prefecture of Illyricum from Nicomedia. Both men were given the title of Augustus. Beneath those two men, each Augustus appointed a Caesar, one to rule Gaul, and the other the East. When an Augustus died or retired, the respective Caesar was to take his place, and name a replacement Caesar. In affect, this would instill a regular succession, an entity that had long been absent from Roman politics.

Chaos Resumes. After several successful years of Diocletian’s Tetrarchy, in 305 AD, Diocletian and Maximian decided to retire. They seemed to have been trying to test the succession process of their government. The succession went terribly wrong, and in just three short years, in 308 AD, six different men claimed the title of Augustus (a position intended for two), while not one Caesar remained. Chaos once again consumed Roman politics, and it had a serious, fragmenting effect on the Roman Empire.

In 308 AD, Diocletian came out of retirement to call a conference in Carnuntum (present day Hainburg, Austria) to settle the various disputes. At the conference, Maximian (who had previously come out of retirement to reclaim his title of Augustus) retired for a second time. However, five men still claimed a position intended for two men. In 311 AD, after familial betrayals, revolt, and death, four men remained:

- Constantine in Gaul

- Maxentius (son of Maximian) in Italy

- Licinius in Illyricum

- Maximinus Daia in the East

Maxentius, Augustus of Italy, was a particularly tyrannical and egomaniacal leader. He was inherently paranoid, and suspected Constantine (next door in Gaul) of conspiring to invade Italy. Maxentius decided to prevent the supposed invasion, by invading Gaul first, and killing Constantine.

The Battle Cry. Constantine learned of Maxentius’ intentions, and decided that he would strike first. However, with 60,000 men on the island of Britain, he only had approximately 40,000 men at his immediate service. In early 312 AD, Constantine led 40,000 men across the Alps, into Italy. He won a collection of battles as he made his way south to Rome, including two against the renowned General Ruricius Pompeianus at Brescia and Verona. While Constantine headed towards Rome, his numbers gradually rose, as he recruited men from the countryside and many of his defeated enemies. When he finally reached Rome, he led an army of roughly 50,000 men, while Maxentius was ingrained inside the walls of Rome with 75,000 men. It was a standoff.

Milvian Bridge. Both Maxentius and Constantine received omens before the battle. Inside Rome, the old Sybilline scrolls told Maxentius that on that particular day, the enemy of Rome would die. Assuming that the enemy of rome was Constantine, and not himself, Maxentius took his troops to the village of Saxa Rubra to Battle Constantine with the Tiber River at his back.

The night before, Constantine claimed to have seen a flaming cross in the sky, with the Greek words en tutoi nika (“in this sign conquer”) inscribed on it. According to legend, the next morning, a ‘voice’ told him to put the symbol of Christ – which he had been shown the night before – on the shields of his men. He did as he was told.

The actual battle details are not well known, however, Constantine did lead the charge of his Gallic cavalry, and his army thoroughly routed Maxentius’ army. The fleeing troops had only one escape route, over the Milvian Bridge, across the Tiber River. There was a massive bottleneck effect at the bridge, and not even Maxentius could get across. Maxentius tried to swim across instead, but his heavy armor dragged him to a watery demise. Constantine had won.

Edict of Milan. Before he invaded Italy, Constantine had made a deal with Augustus Licinius of Illyricum. Licinius agreed to stay out of the fighting, and Constantine agreed to marry the daughter of Licinius. After his victory, Constantine, the sole ruler of the Western Roman Empire, met with Licinius (the emperor of the Eastern Roman Empire after he had defeated Maximinus Daia) at Milan. There they declared the Edict of Milan, which called for religious freedom throughout the Empire. Thus effectively stopping the persecution of Christians.

Afterwards. Eventually, Constantine and Licinius began to fight as well. Consequently, the more Constantine supported Christianity in the Western Roman Empire, the more Licinius persecuted Christians in the Eastern. Finally, Constantine defeated Licinius, and took control over the entire empire.

The Battle of the Milvian Bridge allowed for the Edict of Milan, and for the first time, a period in history, which allowed the Christians to live, safe from persecution. Christianity steadily rose in popularity from that point on.

Constantine never was much of an observant Christian, however, he continued to look out for Christianity throughout his reign, as he believed it had saved him at the Milvian Bridge. The Battle at the Milvian Bridge (which is still in use today) led directly to Christianity being the primary religion of Europe.


100 Decisive Battles by Paul Davis

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