When the Emperor Julian was battling the Persians, he had to pass through Caesarea. St Basil came out to pay him homage. He greeted the emperor and offered him a loaf of barley bread. Julian spurned the gift and vowed to destroy Basil’s monastery and all of Caesarea. He told Basil he would make him eat hay, but Basil warned him that God would avenge him for the insult.

When Basil returned to the city, he assembled the people and told them about Julian’s threat. He ordered them to fast for three days and to hold vigils in the Virgin’s church so that she would stave off the attack.

Basil fell asleep in front of the altar and the Virgin appeared to him with a great host of saints. She promised to avenge Julian and summoned St Mercurio. The Virgin ordered him to take revenge. St Mercurio, riding on a white steed, and brandishing a lance, struck Julian in the middle and killed him. Basil saw all of this in a vision.

When he woke up, Basil called one of his companions and went to look at the place where he had placed the weapons of St Mercurio. When he could not find them, he realised that his dream had been a reality. He gathered the people and told that St Mercurio had killed Julian with a thrust of his lance — a blow better than that of any jouster. He said he had gone to St Mercurio’s tomb and had seen that his weapons were missing.

The people accompanied Basil to the tomb and, this time, they found the weapons there. St Mercurio’s lance was covered in blood, which proved that the Virgin had defended them against Julian. While the people were gazing with wonder at the weapons, a Syrian philosopher named Master Libano approached them. He had been at the battle and confirmed that Julian was dead.

He said he had seen a white knight deliver a great blow to Julian and told them he wished to remain with them and to convert to Christianity. Master Libano was baptised at once and then the people began to celebrate the feast of the Virgin.