Luigi Pirandello's 1921 play "Six Characters in Search of an Author" ("Sei personaggi in cerca d'autore") has the deserved reputation of being the first existentialist drama and having a profound effect on later playwrights.
The father was once married to a peasant woman and had a son by her, but forced her to leave and live with another man. From afar he has watched her new family grow up. The widowed mother is a very emotional woman who has just lost her lover and is the only one of the six who appears to be unaware that she is only a character. The outspoken step-daughter ,who was almost seduced by the father while working as a prostitute, is anxious to play out the scenes so that she can humiliate the father. The son ,an aloof young man who hates his mother for having abandoned him as a child, wants to leave the studio but finds he cannot go until his scene is finally played out. The boy says nothing, because he will die by shooting himself at the end of the play. The child is also silent because she dies at the end in a fountain.
One of the few characters in the drama who has a name is Madame Pace, who is in charge of the dress shop that also serves as a brothel where the step-daughter works.
The radical idea here is that there is an immutability of reality for these six characters. Because they are forms, forced into performing the actions for which they were imagined, there is an inherent conflict with life. This is why the son wants to escape but cannot leave the studio...