Soliloquies have been a common dramatic convention since ancient Greek theatre. In Shakespearean plays, soliloquies are often used to explore the complex emotions and motivations of the main characters, allowing the audience to gain insight into their thoughts and feelings.
Some famous examples of soliloquies include Hamlet's "To be or not to be" speech, Macbeth's "Tomorrow and tomorrow and tomorrow" speech, and Mark Antony's "Friends, Romans, countrymen" speech.