Principal boy in the context of "Travesti (theatre)"

Robert the Devil, or The Nun, the Dun, and the Son of a Gun is an operatic parody by W. S. Gilbert of Giacomo Meyerbeer's grand opera Robert le diable, which was named after, but bears little resemblance to, the medieval French legend of the same name. Gilbert set new lyrics to tunes by Meyerbeer, Bellini, Offenbach and others.

The piece premiered at the opening of the newly rebuilt Gaiety Theatre in London on 21 December 1868. An extravaganza played on a very large scale, it ran for over 120 performances and played continuously in the British provinces for three years thereafter. It also enjoyed several revivals. The original production starred Nellie Farren in the title role – she became the company's leading "principal boy". Several of the other male roles were played by women, as was common in burlesques of the day.

Ellen "Nellie" Farren (16 April 1848 – 28 April 1904) was an English actress and singer known for her roles as the "principal boy" in musical burlesques at the Gaiety Theatre in London. For a quarter of a century there, she was "the best-known star of London burlesque".

Born into a theatrical family, Farren began acting as a child. She made her professional adult debut in 1864 and joined the company at London's Olympic Theatre, performing in Shakespeare, contemporary comedies, dramas and musical burlesques. From 1868 to 1892, she performed at the Gaiety Theatre, which specialised in musical burlesque, becoming famous in the male and principal boy roles, which permitted an actress in the Victorian era theatre to show her legs in tights. Farren gained a large following among the theatre's mostly male audience.