English guests at "De Lantaarn": Sidney, Penn, Locke, Shaftesbury and Toland

Furly became a progressively more visible figure, and his influence was not limited to the confines of Rotterdam. This was partly as a result of his direct involvement in the controversy which flared up in the early sixties within the Dutch and English Quaker communities regarding certain ritual observances connected with the habit of removing the hat during religious functions, as a sign of salutation and formal interaction with one's neighbour. The Quakers were opposed to indulgence in ephemeral external formalities, and profoundly convinced of the absolute pre-eminence of the immediate divine revelation in the heart of each man, in relation to the Bible, to tradition and to man's reason itself. In their heightened spiritualism the Quakers sacrificed all ecclesiastical liturgy in favour of a narrow code of morals and worship which was entirely directed towards obedience to the will of God. This heightened spiritualism of their concept of the "inner light" cost the Quakers their intercourse and friendship with the kindred religious group of the Collegiants who tended towards a more rational interpretation of inspiration and of divine authority.