Renaissance Vitruvianism provides a broad context in which to situate the architecture of Tycho Brahe's Uraniborg, but fails to account for the motivation behind Tycho's design, for how Tycho knew Vitruvian design principles, and for any of Uraniborg's specific features. Identifying Uraniborg as a Palladian design fares even worse. Some of Uraniborg's features can, however, be understood in terms of talismanic ideas such as those circulating in sources such as Agrippa's De occulta philosophia (which Tycho possessed) and Dee's Propaedeumata aphoristica. Of the several kinds of talisman possible, those of interest were intended to manipulate astral influences by mathematical resonance. Regardless of whether Tycho believed in talismanic efficacy, his early meteorological convictions make talismanic motifs a plausible inspiration for Uraniborg's design.