The Perfect Passive is a grammatical construction used to indicate an action that has been completed by the subject but is expressed in a passive voice. In Latin, it combines the perfect participle of the verb with a form of the verb 'esse' (to be) to show that the subject has received the action rather than performed it. This tense is particularly relevant in historical narratives, allowing authors to emphasize the result of actions taken by others, creating a vivid picture of events.