What incident led to Constantine's conversion to Christianity?

in a vision he got before the battle it was of an angel telling him that he was going to win the battle if he converted.

Answer
Constantine believed that he had won his war against Maxentius with the backing of the Christian God. In subsequent years, he claimed that at an earlier stage, probably in Gaul, he had been granted a vision of the Cross in the sky. Eusebius recorded his assertion to this effect nearly a quarter of a century later, while suggesting that he was not entirely sure of its veracity: "This was when I had the honour of knowing him and of being in his company. When he told me the story, he swore to its truth. And who could refuse to believe it, especially when later evidence showed it to have been genuine?...

Around noon-time, when the day was already beginning to decline, he saw before him in the sky the sign of a cross of light." He said it was above the sun, and it bore the inscription, "Conquer with this". The vision astounded him, as it astounded the whole army which was with him on this expedition and which also beheld the miraculous event.

He said he became disturbed. What could the vision mean? He continued to ponder and to give great thought to the question, and night came on him suddenly. When he was asleep, the Christ of God appeared to him and he brought with him the sign which had appeared in the sky. He ordered Constantine to make a replica of this sign which he had witnessed in the sky, and he was to use it as a protection during his encounters with the enemy.

In the morning he told his friends of this extraordinary occurrence. Then he summoned those who worked with gold or precious stones, and he sat among them and described the appearance of the sign. He told them to represent it in gold and precious stones.. ..

At the time I have been describing .. . he resolved to worship none but the God who had been revealed to him."




Interestingly, this reported vision was remarkably similar to an earlier vision of the god Apollo, whom Constantine was said to have seen during his pagan years.

Answer
Constantine attributed his conversion to Christianity to the vision he saw in the sky, presumably of stars (or other stellar objects) that formed the shape of a cross or something cross-like. This happened just before the battle of the Milvian Bridge, in 312.

Answer It is probably more complicated than that. For further discussion, see the related question shown below: "What brought about Constantine's conversion to Christianity?" He is said to have converted to Christianity on his death bed.
Answer
A vision of a christian symbol promised him victory during a crucial battle. He had the symbol painted on the shields of his army. And the result of that battle; he won. Also his father named Constantius, treated Christians with respect unlike other emperors who persecuted them, and prospered. His attitude towards Christians and success as an Emperor of Eastern Rome prompted Constantine to treat Christians with the same respect his father had shown and to be more open to Christianity. He reasoned that God had shown his father favour and so he would do as his father did, but he took it one step further and converted to the faith himself.

Answer
Constantine claimed that he had seen a cross in the sky the day prior to the Battle of the Milvian Bridge, and the Words, "By this sign you will conquer" inscribed in the sky. That night, he said that he had a dream, telling him that the Christian God would ensure his victory. The Christian historian, Eusebius recorded this after Constantine's death, but implied that the emperor was not altogether telling the truth about his vision.


Even before the Battle of the Milvian Bridge, an acolyte had reported that Constantine saw a vision of the god Apollo in the sky, suggesting a pattern that supports Eusebius' scepticism.