Based on four extant letters the famous Polish alchemist Michael Sendivogius wrote to Emperor Rudolf II and his first chamberlain Hans Popp between 1597 and 1602, this paper adds to a growing body of revisionist scholarship on alchemy in Rudolfine Prague. Unlike most of his many rivals - including luminaries such as John Dee and Michael Maier - who hoped for the Emperor's patronage in vain, Sendivogius officially became a courtier at the imperial court in 1594. As such he was in the privileged position of having access to the Emperor and his close advisors. The surviving correspondence shows how the Pole successfully balanced his alchemical promises against Rudolf's expectations for a number of years. The fact that even Sendivogius found it difficult to translate imperial patronage into ready money suggests that Emperor Rudolf II was considerably more circumspect and less gullible than the widespread cliché suggests. Fully contextualised by all available sources on Sendivogius' early career, the four letters emerge as important documents regarding the Polish adept and alchemical patronage in Rudolfine Prague. They also shed new light on the circumstances which led to the writing and publication of Sendivogius' famous treatise De lapide philosophorum (Novum lumen chymicum).