One of the most bitter pamphlet wars of the later seventeenth century was fought between the Society of Friends, or Quakers, who by 1689 had perhaps fifty-thousand followers, and the Muggletonians, a tiny sect which probably had fewer than one-thousand members. Despite the difference in the number of their adherents, the Quakers believed that the dispute with the Muggletonians was so significant that George Fox, William Penn, Edward Burrough, Isaac Penington, and other Quaker leaders attacked the Muggletonians in print. The Muggletonian prophets, John Reeve and Lodowick Muggleton, believed that the Quakers were the greatest enemies of true religion, and they produced a steady stream of anti-Quaker tracts. Some of the accusations on both sides, such as being Antichrist or being worse than the Pope, were common in sectarian arguments, but the conflict reached a sustained height of invective which was rare even in such a contentious age. In Fox's opinion, Muggleton was a “heathen” whose “foul breath … comes from the foul spirit of thy father.” Another Quaker, Thomas Loe, addressed Muggleton as “thou son of perdition and child of the Devil … seed of the serpent and old sorcerer … ignorant sot.” Quaker attacks on the Muggletonians culminated in Penn's assertion that “from the most primitive times there has not appeared … a more complete monster … than John Reeve and Lodowick Muggleton, brethren and associates in the blackest work that ever fallen men or angels could probably have set themselves upon.”