prosopography
noun
pros·o·pog·ra·phy ˌprä-sə-ˈpä-grə-fē 
: a study that identifies and relates a group of persons or characters within a particular historical or literary context
prosopographical
ˌprä-sə-pə-ˈgra-fi-kəl
adjective 
Word History
Etymology
borrowed from German Prosopographie, borrowed from New Latin prosopographia "description of an individual's personal appearance," from Greek prósōpon "face, mask, role, person" + New Latin -graphia -graphy — more at prosopopoeia
First Known Use
1896, in the meaning defined above