How does Miller in the play (The Crucible) make this 17th century farmer into a character capable of holding our interest and sympathies for two hours?

Clearly, Proctor is the protagonist of the play, dominating three of the four acts. What begins as an ensemble rendering of the town’s drama ends in an examination of a decision by one man, the focus gradually narrowed over the course of the play. How does Miller make this 17th century farmer into a character capable of holding our interest and sympathies for two hours?