One day while at Cork, near which his father’s property was situated, he recognized in a shopkeeper of whom he was making some purchases one of the women who had been present at that never-to-be-forgotten meeting held at his father’s house by Thomas Loe. Much pleased at thus discovering an old acquaintance, the conversation naturally turned to religious subjects, and on William’s expressing the wish that he might again see and hear the famous preacher, the Quakeress informed him that Loe was then living in Cork and would hold one of his usual meetings the following day. It is needless to say that young Penn was present on that occasion and his Oxford experience was repeated. Loe’s sermon seemed aimed directly at him, for it was on “the faith that overcometh the world and the faith that is overcome by the world.” As the first part of the sermon, wherein the preacher depicted with glowing enthusiasm the splendid fruits of that faith that overcometh, awoke in the young man’s heart memories of the true peace and happiness that had been his so long as he had remained true to his beliefs, so the second part, dealing with the faith that succumbs to worldly temptations, fell like blows upon his conscience. Bitter remorse for his frivolous life of the last few years overwhelmed him, and Loe, to whom he presented himself at the close of the meeting, perceiving his state of mind, did not fail to strengthen the effect of his discourse by the most solemn exhortations. For a time filial duty and worldly ambition struggled against the voice of awakened conscience, but the latter finally triumphed. Penn now became a regular attendant at the Quaker meetings and belonged, in heart at least, to the persecuted sect. In September, 1667, while present at one of these meetings, usually held with as much secrecy as possible, in order to avoid the jeers of the rabble, the place was suddenly invaded by order of the mayor and all the participants arrested. Finding the son of so distinguished a personage as Sir William Penn among the prisoners, the astonished official offered to release him at once if he would promise not to repeat the offence, but Penn refused to enjoy any advantages over his companions and went with them to prison. While there he wrote to the Earl of Orrery, complaining of the injustice of his imprisonment, since the practice of religious worship could be called neither a criminal offence nor a disturbance of the peace. On receipt of this letter an order was given for his immediate release, but the report that he had joined the Quakers quickly spread, calling forth both derision and indignation among his friends at court.