Main articles: Shakespeare's plays and William Shakespeare's collaborations
Most playwrights of the period typically collaborated with others at some point, and critics agree that Shakespeare did the same, mostly early and late in his career. Some attributions, such as Titus Andronicus and the early history plays, remain controversial, while The Two Noble Kinsmen and the lost Cardenio have well-attested contemporary documentation. Textual evidence also supports the view that several of the plays were revised by other writers after their original composition.