He was a victim of the fabricated Popish Plot, and was wrongfully executed for conspiracy to murder King Charles II.

On the Feast of the Assumption, 15 August 1678, he took his final vows to the Society of Jesus at Boscobel House, the home of the Penderel family, who were famous for sheltering Charles II after he fled from his defeat at the Battle of Worcester in 1651.

The ceremony was followed by dinner, and the guests then viewed the Royal Oak, the tree in which the King had hidden after fleeing from Worcester.

A bench of seven judges tried them, headed by the Lord Chief Justice, Sir William Scroggs, a firm believer in the Plot, and deeply hostile to Catholic priests in general.

[5] Gavan, who acted as the spokesman for all the five accused, mounted a spirited defence, which led a modern historian to call him one of the ablest priests of his generation.

As an act of clemency, King Charles II (who was convinced of their innocence, but believed that he could not risk inflaming public opinion by issuing a royal pardon) gave orders that they should be allowed to hang until they were dead, and thus be spared the usual horrors of drawing and quartering.