owners of the Globe theatre in 1599 and on May the 19th, 1603, he received a patent, titling him as one of the King’s Men (previously called the Chamberlain’s men) and a Groom of the Chamber by James I, the then King of England. This honour made William a favorite for all court performances, earned each King’s man extra money (30 pounds each for a performance in 1603 alone) and made the Bard's name one rather above reproach. Macbeth which celebrates King James I ancestor Malcolm, is considered to have been written in part as appreciation for the King’s patronage. And as a potent form of royalist propaganda (it warned of the dangers of killing a King appointed like James, by God).
The First Folio (1623): Conclusive proof that Shakespeare authored his plays.
The proof most often cited that Shakespeare authored his plays however, was the First Folio (1623) where Henry Condell and John Hemminges who were actors in the Bard's theatre company, claim in a dedicatory verse within the Folio that they recorded and collected his plays as a memorial to the late actor and playwright. In terms of value, the First Folio originally was sold for just 1 Pound in 1623. Today as one of just 250 still in existence, it would fetch nearly 3 million dollars (US).
Ben Jonson criticizes and then praises William by name.
Further proof of authorship comes in the form of a poem by Ben Jonson, one of the Bard's more friendly rivals, which criticizes the playwrights dramatic plays. It is contained within a work entitled Discoveries (also known as Timber) dated 1641. Despite his criticism, Ben Johnson paradoxically also said that Stratford's famous Bard's works were timeless, describing them as "not of an age, but for all time".