Gustav Holst is rarely thought of as an opera composer. Though his success and enduring fame rests primarily in orchestral and choral works, such as The Planets and The Hymn of Jesus, opera was the only genre in which he maintained a steady output across his entire career. Holst'e(tm)s operatic repertoire begins with unpublished student works such as Lansdown Castle and The Revoke, continues through the better-known Sanskrit operas, and concludes with The Wandering Scholar, one of his last compositions. These works provide a gateway to the exploration of how a budding opera composer negotiated the British operatic world across his career and how his synthesis of a myriad of cultural influences in his operatic works affected his reputation and success as a composer. This interdisciplinary study provides a kaleidoscopic view of how overlapping and often contradictory cultural influences such as imperialism, religion, literature, indigenous theatre, philosophy, folk culture, nationalism, and historiography are reflected in Holst'e(tm)s operas and figure into his reception as a composer of operas. Holst emerges as a seminal figure in the British operatic world and a composer much more interested and engaged with British culture than previous historiography has led us to believe.