According to tradition the church was built in the sixth century, on the site of a Pagan temple, and an image of an idol was buried under the foundations of each of the pillars. What is certain is that into two of the piers are inserted figures in alabaster from a Roman monument, and that numerous votive tablets and inscriptions are walled into the church. The beautiful woodwork of the western choir escaped being blown to splinters by a happy accident in 1596.
On Sunday, the Feast of S. Michael, the bishop occupied his throne at mass. When he stood up for the Gospel, his foot broke through the floor of his stall. He drew his foot out, and after the conclusion of the Creed proceeded to the pulpit to preach. Whilst he was away a choir boy looked into the hole made by the bishop's foot, thrust in an arm and drew out his hand full of a black powder, which he showed to an officer standing by, who at once recognised that this was gunpowder. A search was made, and it was found that enough gunpowder had been rammed in under the throne to blow bishop and chapter up, and wreck the church. A fuse had been inserted through a hole bored in the woodwork, and it was supposed that the purpose was to light this when the bishop returned from the pulpit. A messenger was at once sent to him, but he refused to desist from his sermon, calmly proceeding with it to the conclusion, although the congregation, who had received wind of the attempt, had begun to clear out of the church. He returned to his throne and remained there to the end of the service. It was never ascertained by whom the plot was arranged, whether by Huguenots, or whether it was due to private malice.
