Johann Jakob Greber was a German Baroque composer and musician. His first name sometimes appeared in its Italianized version, Giacomo, especially during the years he spent in London. Greber composed solo cantatas, sonatas, and stage works, including the opera Gli amori di Ergasto which opened London's Queen's Theatre in 1705. He died in Mannheim, where for many years he was Kapellmeister of the court orchestra of Charles III Philip, Elector Palatine.

His Majesty's Theatre is a West End theatre situated in the Haymarket in the City of Westminster, London. The building, designed by Charles J. Phipps, was constructed in 1897 for the actor-manager Herbert Beerbohm Tree, who established the Royal Academy of Dramatic Art (RADA) at the theatre. In the early decades of the 20th century Tree produced spectacular productions of Shakespeare and other classical works, and the theatre hosted premieres by such playwrights as Bernard Shaw, J. M. Synge and, later, Noël Coward and J. B. Priestley. Since the First World War the wide stage has made the theatre suitable for large-scale musical productions, and His Majesty's has accordingly specialised in hosting musicals. It has been home to record-setting musical theatre runs such as the First World War hit Chu Chin Chow and Andrew Lloyd Webber's The Phantom of the Opera, which has run at His Majesty's since 1986, except during the COVID-19 pandemic theatre closures.