John Victor Murra, Rowe's near-contemporary researcher from the United States, was born in Eastern Europe and helped develop this research tradition. Some of the greatest ethno-historians of time, Maria Rostworowski and Franklin Pease, also emerged at this time. Murra's work was methodologically significant because he generated a research framework and a group of disciples that tested his ethnohistorically generated ideas with archaeological data. Marisol de la Cadena notes: In 1952, while still a graduate student at the University of Chicago, Murra traveled to Jamaica, hired by his friend, American anthropologist Sydney Mintz, and then traveled to Puerto Rico under auspices of Julian Steward. In 1956, Murra finished his doctoral dissertation at the University of Chicago, a work that would become one of the most influential in understanding Inca economic organization. Murra's doctoral thesis, "The Economic Organization of the Inca Empire", was clearly in this tradition and provided a deeper materialist understanding of Inca society.