group convened by Theodore Haak. This group is now often called simply the “1645 group”. George Ent, Francis Glisson and Charles Scarborough joined around 1647. Wallis mentions also John Wilkins, Samuel Foster and Christopher Merret. The group broke up around 1648. There are in fact two accounts by Wallis, the first from 1678, and the second (unpublished at the time) from 1697. The first version (A Defence of the Royal Society) was produced to contradict William Holder, with whom Wallis was in dispute over his work in speech therapy. The second version was published in 1725 by Thomas Hearne, in front matter to his edition of the chronicle of Peter Langtoft; from where in 1756 Thomas Birch picked it up as an authority on the origins of the Royal Society, and argued against Sprat's history as superficial on its formation. Some doubts have been cast on Wallis's accounts as authoritative. Haak was an associate of Wallis through the religious activities of the Westminster Assembly; it has been questioned whether his role was a central as Wallis suggested. On the other hand Haak had other associations (with Marin Mersenne; with John Pell and Gabriel Plattes of the Hartlib Circle). Margery Purver has argued that Sprat's History is more reliable for the purposes of the Royal Society, their reading of Francis Bacon's thought, and the intention to develop science according to a taxonomic approach. Relationship with other groups While the traditional account, from Thomas Birch in the eighteenth century, identified the 1645 Gresham group with the "invisible college" mentioned in correspondence of the young Robert Boyle from 1646 and 1647, this is now generally doubted. Other candidates for the Invisible College mentioned in Boyle's letters are regarded as more plausible: the "Comenian" part of the larger Hartlib Circle, and the group that probably substantially overlapped it gathered by Lady Ranelagh, Boyle's sister. Margery Purver identifies it in more specific terms among Hartlib's associates, those supporting the institution of an "Office of Address". Apart from Boyle himself, the only figure identifiable with the "invisible college" (under this description) to have played a leading part later in the Royal Society is William Petty. On the other hand during the 1650s Henry Oldenburg came to know Boyle and others, both in the Oxford and the Hartlib group, through similar contacts. Both John Wilkins and John Wallis moved to Oxford in 1648, shortly after the end