My current research focuses on equine breeding programs at Herrenhaus in Hanover, Germany in the eighteenth and nineteenth centuries: the period in which the modern notion of “breed” was being developed. Among the horses bred at Herrenhaus were unusual two strains, called “issabellen” (“cream”) and “weissgeborn” (“white”). The “creams” became symbolic of the British Crown, while the “whites” represented Hannover’s heraldry. My research suggests that these colors (which differ from modern cream or white) would be very difficult to reproduce reliably without an understanding of how these traits were inherited. Indeed, the way in which the selection and breeding of these animals was historically discussed suggests that while the knowledge was not particularly common, those involved recognized the complexities of multi-trait inheritance. Although Leslie Kathman’s 2014 Equine Tapestry has opened discussion about historical genetics, it is aimed primarily at modern breeders and often glosses over issues of interest to historians. In addition to identifying what traits were available to (and valued by) historic horsemen, my chapter will consider how breeders understood the production of animals to serve increasingly specific requirements of emerging breed discourse.