The earliest mention of Shakespeare’s Twelfth Night is in a notebook of gossip, observations and sermon notes kept by John Manningham while a law student at Middle Temple, one of the Inns of Court in London. After seeing a private performance of the play at the Middle Temple, he observes that it resembled The Comedy of Errors, Plautus’s Roman play Menaechmi, and an Italian play called GI’ingannati. He then recounts his favorite subplot: Olivia’s steward Malvolio is tricked into thinking she loves him by a forged letter written by her servant Maria, which results in his public humiliation and imprisonment. The scene in which Malvolio parades before Olivia, smiling largely in cross-gartered yellow stockings, is a favorite of audiences today as well.

Five weeks later (and in the same manuscript), Manningham records an amusing story: Shakespeare had overheard Richard Burbage and a woman planning a tryst after a performance of Shakespeare’s Richard III. When Burbage went to meet the woman, Shakespeare was already with her, and sent a cheeky message to him that “William the Conqueror was before Richard III.” To clarify the joke, Manningham adds a reminder that Shakespeare’s first name was “William.” He cites the source of this anecdote at the end of the entry, but the name is difficult to read. Scholars have long debated whether it reads "Mr. Touse," that is, William Towse, a frequent informant in the diary and a member of the Inner Temple, or Manningham's roommate Edward Curle, another name that appears frequently. Curiously, Curle tells a similar story about Thomas Bodley, founder of the Bodleian Library, who, learning that "a rich widow" was about to be matched to someone else, intercepted her and won her hand in marriage (fol. 46).

A deleted word in the first line of the entry has not been included in previous published editions: “a play called mid Twelue night…” (In his 1976 edition of the diary, Robert Parker Sorlien notes the struck-through word in a footnote on p. 12). Did Manningham accidently begin referring to another Shakespeare play, Midsummer Night’s Dream, before correcting himself?

The notebook was first noticed by John Payne Collier in his Annals of the Stage, vol. 1, p. 320 (1831).