Gwendolyn Midlo Hall, who after years of digging through obscure libraries in Louisiana, Spain and France managed to rescue the identities of more than 100,000 enslaved people from archival oblivion and demonstrate the vast extent of African influence on America’s cultural heritage, died on Aug. 29 in Guanajuato, Mexico, about 200 miles northwest of Mexico City. She was 93.

Her son Haywood Hall said her death, at his home, came after a recurrence of breast cancer and a stroke.

Dr. Hall led a colorful early life as a civil rights activist and spent the bulk of her academic career at Rutgers University, where she taught Latin American history. It was only at the end of that time, and later in retirement, that she left her true mark on the fields of colonial and African American history.

For much of the 20th century, most historians assumed there was little material to be found about enslaved Africans in the colonial era — their origins, and even many of their names, were assumed lost.

Dr. Hall showed that this was not the case, at least in Francophone North America. While conducting research in a rural courthouse in southern Louisiana, she discovered a record book in which French colonial notaries had documented in precise detail the identities of thousands of enslaved Africans brought to Louisiana in the 18th century.