They devote themselves to three years of study and fasting; Berowne agrees somewhat more hesitantly than the others.
The King declares that no woman should come within a mile of the court.
Berowne confesses to breaking the oath, explaining that the only study worthy of mankind is that of love, and he and the other men collectively decide to relinquish the vow.
Arranging for Holofernes to entertain the ladies later, the men then dress as Muscovites and court the ladies in disguise.
The play's sophisticated wordplay, pedantic humour and dated literary allusions may also be reasons for its relative obscurity, as compared with Shakespeare's more popular works.
Love's Labour's Lost was staged rarely in the 19th century, but it has been seen more often in the 20th and 21st centuries, with productions by both the Royal Shakespeare Company and the National Theatre, among others.
It has also been adapted as a musical, an opera, for radio and television and as a musical film.
Impressed by the ladies' wit, the men apologize, and when all identities are righted, they watch Holofernes, Sir Nathaniel, Costard, Moth, and Don Armado present the Nine Worthies.
The four lords – as well as the ladies' courtier Boyet – heckle the play, and Don Armado and Costard almost come to blows when Costard reveals mid-pageant that Don Armado has got Jaquenetta pregnant.