How did Sophocles change the number of actors in Greek tragedy?

Sophocles is credited with the major innovation of introducing a third actor to the Greek stage.12

Prior to this development, Greek tragedy typically utilized only two actors, who would often "double" by playing multiple roles throughout a performance. By adding a third actor, Sophocles significantly expanded the possibilities for dramatic storytelling. This change allowed for a greater number of characters to appear in a single play and enabled more complex and fluid interactions between them. Consequently, the scope of dramatic conflict was extended, providing dramatists with more flexibility to create intricate situations.12