"Verisimilitude" is the neoclassic principle of truth. Neoclassical tragedies must be easily comprehended and accepted as true by the audience. This is accomplished by using generalities or archetypes that are readily accessible to everybody. For instance, members of the higher class will act as everybody perceives members of the higher class to act, women will act as women and so on. A Neoclassical tragedy must also mimic reality and leave out anything that is otherworldly or supernatural.
Continuing with the generality and archetype principle, a tragedy must adhere to the rules of a tragedy and not cross into comedy. According to Neoclassical principles, tragedy should be centered around lofty characters, that is, characters who are of the ruling or noble classes; tragedy must deal with lofty, epic plots, such as the murder of a queen; and a tragedy must end in tragedy. The form also often follows the five-act form outlined by Horace.
Neoclassical drama is meant to instruct. Each Neoclassical tragedy or comedy must impart a moral lesson onto the audience. These lessons often deal with the faith, honor, good and evil, and in each case, justice must be served.
The three unities, as defined by Aristotle, are time, place and action. First, the plot of the play must elapse within the real time of the play. This means that a play cannot span a week, month or year but must be confined to the length of the production, which is generally a few hours. Second, the play cannot be set in places separated by large amounts of space but instead must be concerned with one or two locations that are reasonably traversable in the given time of the play. Finally, there can only be one plot or line of action throughout the play, which means no subplots.
As people moved away from Neoclassical tastes toward Romanticism at the end of the 18th century, domestic tragedy began to gain popularity. Domestic tragedy focused on common people and their problems. For instance, the main character may be a merchant instead of a king. A good example of this kind of tragedy is George Lillo's "London Merchant."