To obtain the ius imaginis right required obtaining one of the curule magistracies:
- curule aedile,
- praetor,
- censor, or
- consul.
Ancestral maps were displayed in the cupboards (armaria) of the family atrium, and were considered symbols of high status. They were displayed during special festivals and public sacrifices, as well as in funerals and in the atrium.
Pollini says there is substantial evidence that the wax ancestral mask began in the second half of the 4th century B.C., after the passage of the Lex Licinia Sextia [367 B.C.] requiring that at least 1 consul be plebeian and later laws that led to the creation of a new, plebeian nobility. By obtaining a curule office, such a plebeian became a noble, a novus homo, and entitled to the ius imaginis. This was also the time the Senate first sanctioned theatrical performances (ludi Scaenici), which is worth noting, given the theatricality involved in the funeral parade.
Source:
Performing Death: Social Analyses of Funerary Traditions in the Ancient Near East and Mediterranean #13 "Ritualizing Death in Republican Rome: Memory, Religion, Class Struggle, and the Wax Ancestral Mask Tradition's Origin and Influence on Veristic Portraiture." John Pollini, University of Southern California.
The first literary reference to the imagines comes from the second century B.C. in Plautus' comedy Amphitruo.

