All observers of 16th-century France commented on the scarcity of horses that plagued the kingdom. In spite of their key role in French horse breeding, aristocratic stud farms were of no more help in that regard than the Valois royal stud farmsThe archives of the House of Guise provide us with an opportunity to look closely into the workings of such an aristocratic stud farm and to understand why those facilities couldn’t solve the problem of horse breeding in France. The Guise stud farm, located in Éclaron, was a complex organization spread over three different locations where a highly trained staff could develop sophisticated raising techniques. The Guises’ investment in their stud farm was both symbolical and financial: the breeding of good horses meant to join the duke’s stables would balance the breeding costs, and careful selection would help create the duke’s own race, which would then mirror the aristocratic lineage. Aristocratic stud farms thus served the purposes and endeavours of each House – not necessarily those of the kingdom.