Returning to the Iberian Peninsula, this chapter considers how colonial experiences influenced early modern views of horse breeding. King Philip II’s survey of horse breeding in Spain and his efforts to develop a new royal “race” (raza) of horses provide two valuable case studies of contemporary debates about improving horse breeds. Knowledge and expertise gained from active horse breeding often contradicted ideal values of lineage or blood purity. These cases acknowledge limits to the control implied in selectively breeding domesticated animals and demonstrate an early modern understanding of the contructedness of horse breeds. In a larger sense, these findings offer a nuanced reading of how raza and casta in animal husbandry relate to histories of racial terminology and classifications of difference in the Spanish empire.

As the Spanish empire expanded, the growing abundance of horses elevated an underlying tension between two colonial goals: to populate land with horses bred in new settlements, and to control land in new settlements by regulating the movement, reproduction, and possession of horses in them. The horse population increased due to both evolutionary environmental affinities and the use of traditional husbandry methods, such as loose herd management and protection of the commons, which had some unintended consequences. The responses of Spanish and Indigenous actors to these changes presented opportunities to negotiate the perception of and exercise of Spanish imperial power in a new equine political ecology.

Colonial horse breeding regulations attempted to manage and classify equine difference, but conceded to the numerous challenges in establishing desired physical traits. Likewise, emerging feral horse herds challenged narratives of Spanish domination over colonial environments. Importantly, these feral horses were a direct product of Spanish husbandry methods that used both controlled and uncontrolled breeding. In this sense, both the free-ranging horses and selectively bred colonial horses illustrated the limits of domestication in their diverging from human efforts to intervene and control them.

Horses represented an expensive and logistically challenging aspect of early expeditions, as they had to be brought by boat and then bred in colonial settlements to aid in expansion. This scarcity only elevated the cultural and political significance of horses, evident in the narratives of early Spanish or Indigenous chroniclers and also in strategic efforts to breed horses in colonial settlements, despite the challenging and varied new environments. Beyond the military lore of conquest, horses literally and materially served as the measure for establishing social status, access to political office, and territorial control by colonial representatives, shaping the structure and strategy of colonial expansion in powerful ways.