In 1863 an American archaeologist acquired a skull from a Peruvian antiquarian in Cuzco, inciting a debate over the complexity of "ancient" surgery worldwide. The skull had been found in the Inca estate of Yucay, and the quadrilateral hole in its frontal bone suggested that it had been trepanned—a medical operation to relieve pressure upon the brain. This lecture reconstructs the process bywhich "Inca trepanation" became an accepted scientific fact, and the looting and trade in "Inca" and Andean ancestors and crania it relied upon to provide further museum "specimens" to prove or disprove Indigenous skillat this high-risk maneuver. Central to this process was the work of Andean collectors and Peruvian surgeons like the anthropologist Julio C. Tello, whose authority was sought but effaced by Americanist anthropologists in the United States. The comparison of their surviving museums and displays in Lima and Washington, DC reveals how we can re-collect the more radical and anti-racist knowledges in the collections these Andean actors helped build, to imagine their re-encounter as "scientific ancestors" today.