He watched with lively interest the work of organisation which Fox was carrying on in so masterly a fashion. When John Perrott caused a disturbance, by refusing to remove his hat whilst praying in public, or William Rodgers obstructed Fox's path, mistaking discipline for tyranny, none were more ready than he to rally round the trusted leader. In 1677, he joined Fox, Barclay, and others, in a visit to Holland, to organise and consolidate the Society there, and to visit such promising enquirers as the Princess Elizabeth, the Countess de Hornes, and the courtly Van Helmont. He published a full and glowing account of the religious services in which they were engaged, which gives us a vivid picture of the "times of refreshing" which the brotherhood enjoyed in its early days. The next year, 1678, when reports of Popish plots kept the nation in a constant alarm, he was twice heard before a committee of the House of Commons, in support of a petition which he presented on behalf of the Society of Friends. Their inability to take an oath, led to their being caught in the meshes of an Act intended for Catholics. William Penn explained their position with dignity and great candour. With characteristic boldness, though asking for a favour, he did not flinch from pleading for full liberty of conscience even for the hated Papists. The committee listened respectfully, and adopted his suggestions for the relief of Friends; but the sudden prorogation of Parliament prevented the bill from being carried.