One of the chief measures by which Ranavalona maintained order within her realm was through the traditional practice of trial by the ordeal of "tangena". A poison was extracted from the nut of the native "tangena" ("Cerbera manghas") shrub and ingested, with the outcome determining innocence or guilt. If nobles or freemen were compelled to undergo the ordeal, the poison was typically administered to the accused only after dog and rooster stand-ins had already died from the poison's effects, while among members of the slave class ("andevo"), the ordeal required them to immediately ingest the poison themselves. The accused would be fed the poison along with three pieces of chicken skin: if all three pieces of skin were vomited up then innocence was declared, but death or a failure to regurgitate all three pieces of skin indicated guilt. According to 19th-century Malagasy historian Raombana, in the eyes of the greater populace, the "tangena" ordeal was believed to represent a sort of celestial justice in which the public placed their unquestioning faith, even to the point of accepting a verdict of guilt in a case of innocence as a just but unknowable divine mystery.