How Constantine’s Victory at The Milvian Bridge Led to the Spread of Christianity

History Hit

4 mins

28 Oct 2016

On 28 October 312 two rival Roman Emperors – Constantine and Maxentius -faced up against each other at the Milvian Bridge in Rome. Constantine famously saw a vision before the battle which persuaded him and his army to paint the symbols of Christianity on their shields. Just a year after the battle, the victorious Constantine made this obscure eastern religion official within the Roman Empire – with momentous consequences.

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Diocletian restores order to Rome

The 3rd century was a chaotic one for Rome – but by the end of it the Emperor Diocletian appeared to have finally found a system for governing such a vast Empire which actually worked.

Diocletian was the first to suggest devolving powers in the Empire, and he created spheres of influence each governed by their own mini-emperor, or Caesar, in what is now known as the Tetrarchy. Diocletian was a highly capable Emperor who was able to keep things under control during his rain as Augustus or overall Emperor. However, when he stepped down in 305 the consequences were inevitable – and every mini-emperor decided to fight each other for the greatest prize in the world – ruling all of Rome’s dominions alone.

The Caesar (interchangeable with Emperor)  of the north-west was called Constantius, and after a successful rule and campaigns in Britain and Germany he had gained a lot of support in his lands. Suddenly, in 306 he died, and Diocletian’s system began to collapse.

Diocletian’s tetrachy. Diocletian himself ruled the rich eastern provinces of the empire.

From a harsh Roman frontier…

As he lay dying in what is now York, he declared his support for his son Constantine to be crowned as Augustus now that Diocletian had gone. Constantius had just been campaigning north of Hadrian’s Wall, and when his troops heard of this declaration they enthusiastically supported it and proclaimed Constantine to be the rightful Augustus of the Roman Empire.

Constantius’ lands of Gaul (France) and Britain quickly offered their support for his son after he began to march south with this triumphant army. At the same time in Italy Maxentius – the son of a man who had ruled with Diocletian – was also proclaimed Augustus and was widely regarded as the favourite to make his claim a reality.

With two eastern claimants also vying for the throne, the canny Constantine stayed where he was and let them fight each other over Rome for the next few years. By 312 Maxentius was victorious and war between him and the pretender in Britain seemed to be inevitable.

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…to the Roman capital

In the Spring of that year the bold and charismatic Constantine decided to take the fight to his enemy and marched his British and Gallic army across the Alps into Italy. Winning stunning victories against Maxentius’ generals at Turin and Verona, only the rival Emperor himself now barred Constantine’s access to Rome.

By 27 October the two armies were encamped near the Milvian Bridge other at the outskirts of the city. Battle would be joined the next day, and with over 100,000 men on both sides it promised to be exceptionally bloody.

Constantine gives a remarkable order

That evening, as thousands of doomed men prepared for battle, Constantine is said to have had a vision of a burning Christian cross in the sky. Some have tried to dismiss this as a result of unusual solar activity, but it had a profound effect on the Emperor. In the morning he decided that this sign meant that the Christian God – then still the subject of an unremarkable cult religion – was on his side, and he ordered his men to paint the Greek Christian Chi-Rho symbol on their shields.

After the battle this symbol would always decorate the shields of Roman soldiers.

Maxentius positioned his men on the far side of the bridge, which had been partially destroyed and was now fragile. His deployment quickly proved to be foolish. Constantine, who had already proved himself to be an excellent general, routed Maxentius’ cavalry with his own experienced horsemen, and then Maxentius’ men began to edge back for fear of being outflanked. But they had nowhere to go.

With the river Tiber at their backs, the only place they had to go was over the bridge, which could not bear the weight of so many armoured men. It collapsed, and plunged thousands, including Maxentius, into the fast-flowing water. He was killed, like many of his men, by the weight of his armour and the strength of the current.

His troops still stranded on Constantine’s side of the river were now outnumbered and surrendered, apart from the dead Emperor’s Praetorian Guard who all fought to the death. By the evening Constantine was utterly victorious, and he would march jubilantly into the capital the next day.

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The unprecedented rise of Christianity

Though Constantine would prove to be a good Augustus who re-united all of Rome’s lands under one banner, the most important consequence of the victory was religious. He ascribed the victory to divine intervention, as the collapse of the bridge at a crucial moment showed.

In 313 the Emperor issued the Edict of Milan – declaring that from now on Christianity would be an official religion of the Empire. For such an obscure – and unusual – eastern religion to be made official in such an enormous Empire was as unexpected as the United States becoming a strictly Sikh country today. The momentous consequences of this decision still dominate our lives in the west today, and the Christian ethic and worldview has shaped the world perhaps more than any other.