Her father was Jan Jacek Rostworowski, a Polish aristocrat, and her mother, Rita Tovar del Valle, was from Puno.

[1] Diez-Canseco, who would later become the General Departmental Secretary of the Popular Action political party, played a great role in fostering Rostworowski's historical interests.

After the sudden death of her husband in March 1961, she moved to the leper colony of San Pablo, directed by the German Maxime Kuczynski-Godard, to work as a missionary.

At the university, two of her teachers were Raúl Porras Barrenechea, who introduced her to historiographical proceedings and to the analysis of historical sources, and the North American anthropologist John Murra, who motivated her to begin studying ethnic history.

One of the publications that she edited is called Historia del Tahuantinsuyo, the highest-selling social science journal in all of Peruvian history.

She also made important and acclaimed investigations into the field of precolumbian societies on the Peruvian coast, a topic which had not been widely studied until then.

She presided over the Peruvian Association of Ethnic History (Asociación Peruana de Etnohistoria), which was founded in Lima in 1979 by Fernando Silva Santisteban.