The lawsuit says the images are the “spoils of theft,” because as slaves Renty and Delia were unable to give consent. It says that the university is illegally profiting from the images by using them for “advertising and commercial purposes,” such as by using Renty’s image on the cover of a $40 anthropology book. And it argues that by holding on to the images, Harvard has perpetuated the hallmarks of slavery that prevented African-Americans from holding, conveying or inheriting personal property.

“I keep thinking, tongue in cheek a little bit, this has been 169 years a slave, and Harvard still won’t free Papa Renty,” said Mr. Crump, who in 2012 represented the family of Trayvon Martin, an unarmed black teenager killed by a community watch member in Florida. Ms. Lanier is also represented by Josh Koskoff, a lawyer who represents families of the Sandy Hook elementary school massacre victims.

Renty and Delia were among seven slaves who appeared in 15 images made using the daguerreotype process, an early form of photography imprinted on silvered copper plates.

The pictures are haunting and voyeuristic, with the subjects staring at the camera with detached expressions.

The daguerreotypes were commissioned by Louis Agassiz, a Swiss-born zoologist and Harvard professor who is sometimes called the father of American natural science. They were taken in 1850 by J.T. Zealy, in a studio in Columbia, S.C.

Agassiz, a rival of Charles Darwin, subscribed to polygenesis, the theory that black and white people descended from different origins. The theory, later discredited, was used to promote the racist idea that black people were inferior to whites. Agassiz viewed the slaves as anatomical specimens to document his beliefs, according to historical sources.