Later the 7th (City of London) Battalion London Regiment, which claimed descent from the Yellow Regiment of London Trained Bands, adopted the tune as its quick march during World War I, replacing "Austria" (to the same tune as Deutschland über Alles), which had been used until then.[15] Ralph Vaughan Williams's Fantasia on "Greensleeves" (1934), based on the "Greensleeves" melody, is actually an arrangement by Ralph Greaves (1889–1966) of an orchestral interlude from Vaughan Williams' 1928 opera Sir John in Love; the fantasia also incorporates the folk song "Lovely Joan" as its middle section.[16][17][18][19] A rendering of the tune replaced the whistled "Lassie Theme" and was used extensively in later seasons of the Lassie television show, especially during the ending credits.[20] In Hong Kong Diploma of Secondary Education Examination, Hong Kong Advanced Level Examination and Hong Kong Certificate of Education Examination (public exams in Hong Kong), this song is used as background music for candidates to study the questions and tidy up their answers in listening papers.[21] In the TV series Mr. Sunshine, "Greensleeves" is the music being played in Eugene Choi's music box several times along the series.