The wealthy wine merchant Saull was a shadowy, underworld kingmaker, and very little known. What snatches of family information we have come from his nephews in the pub trade, and suggest a freethinking family milieu. It is clear that as a young man he was never as illiterate as the press later had it. Being an autodidact he was obsessed with rational schooling programmes—and this provides a baseline for understanding his museum: it was to counteract Sabbath Scriptural teaching and prepare artisans for power in the expected socialist millennium. A costly museum and dissident philanthropy depended on Saull’s wine profits. Study of the wine trade in the 1820s-1840s shows why he could afford to build his fossil empire in London’s salubrious Aldersgate Street. From the first we find Saull in 1828 throwing heterodox science in his vicar’s face. Freethought, republicanism, and radicalism marked Saull out, not only in the parish, but as a merchant in the City of London. Like many ‘infidels’ he was indicted (although never jailed) in an age when Christianity was called the law of the land. Atheists were widely vilified (“vermin”, the evangelical geologist Hugh Miller called them). But in the radical City it was different. We examine how his views affected his City prospects—indeed, what it meant to be a ‘merchant’. And we see how a prominent museum could provide an uneducated trader his bona fides, and act as a mediating forum for the politically disparate. Ultimately Saull’s scientific assets, his fossils, were made to do social work, and we reveal how, in an age of inequality and poverty, the stones were shown to be pregnant with promise for a brighter human future.