In 1690 Thoresby made the acquaintance of William Nicolson, an eminent antiquarian scholar and later Bishop of Carlisle, and from this point turned his mind towards the production of a history of Leeds and environs. Throughout the last decade of the century, his fame as an antiquarian slowly rose, as did the public attention paid to his museum – an object of curiosity to strangers visiting the city. As a result of his studies of Roman remains, he was elected Fellow of the Royal Society in 1697; some of his communications appear in their transactions. In the same year he was elected an Assistant, or Common-Councilman, in the Corporation of Leeds. He abandoned his connections with the dissenters in 1699.