It shows the perfect independence of Penn's mind that though he was on good terms with the King, he risked giving offence by his open and hearty sympathy with Algernon Sidney. That patriot, after long years of banishment was allowed to return home in 1677. Soon after, he yielded to the representations of his republican friends, and sought a seat in Parliament. First he tried Guildford, and then Bramber; but was not only hotly opposed by the court, but dishonourably and illegally tricked out of the seat. All through the struggle he had the enthusiastic and vigorous support of Penn, although at the time the affairs of Pennsylvania were far from settled, and he had so much reason to wish to keep the royal favour. Usually Penn kept clear of party politics, but on this occasion he canvassed and spoke for his friend with great zeal; so that the French Ambassador speaks of him and Sidney as the two trusted leaders of the republican party. But though Penn's action proves that he did not share the scruples of most of his brethren against participating in political affairs, yet it was probably the man and his principles that won his confidence, rather than the party with which he acted. Probably, Penn would have endorsed the early opinion of his father-in-law, Isaac Pennington, who wrote, (1651) "Whoever they are, whom I saw fitted for it (Government) and called to it, they should have my vote on their behalf." In the midst of politics and schemes of emigration, the stream of his polemical works still continued to flow, and every year saw one or more pamphlets from his pen. Turning to his private life, in 1680, he lost his beloved father-in-law, Isaac Pennington. Though gifted with a refined mind and a loving heart, he had a nature far less robust and vigorous than his son-in-law, who shortly after his death edited his collected works. But a heavier blow followed. In 1682, Lady Penn died, and her death seems to have made him seriously ill for some time. She had clung to him when his adoption of Quakerism turned his father against him, and she took care of him when he was turned out of doors. She never accepted Quakerism, yet probably her gentle and loving nature had an influence with her son that the stern father never had.