"Incestum" (that which is "not "castum"") is an act that violates religious purity, perhaps synonymous with that which is "nefas", religiously impermissible. The violation of a Vestal's vow of chastity was "incestum", a legal charge brought against her and the man who rendered her impure through sexual relations, whether consensually or by force. A Vestal's loss of "castitas" ruptured Rome's treaty with the gods "(pax deorum)", and was typically accompanied by the observation of bad omens "(prodigia)". Prosecutions for "incestum" involving a Vestal often coincide with political unrest, and some charges of "incestum" seem politically motivated: Marcus Crassus was acquitted of "incestum" with a Vestal who shared his family name. Although the English word "incest" derives from the Latin, incestuous relations are only one form of Roman "incestum", sometimes translated as "sacrilege". When Clodius Pulcher dressed as a woman and intruded on the all-female rites of the Bona Dea, he was charged with "incestum".