Emil Anton Joseph Friedrich Kreuz, also known as Emil Frederick Thornfield, (25 May 1867 in Elberfeld – 3 December 1932 in London) was a German violinist, violist, teacher, conductor and composer.Emil Kreuz began playing violin at an early age and studied under Georg Joseph Japha (1835–1892) in Cologne from the age of ten. At sixteen he won a scholarship at the Royal College of Music in London, where he studied violin with Henry Holmes and composition with Charles Villiers Stanford until 1888. For two years he concentrated his studies on the viola, making his debut as soloist with Hector Berlioz's Harold en Italie in December 1888 at one of the London Symphony Concerts established by George Henschel. He became well known in England. He was violin soloist at the Leeds Festival in 1889, violist of the Gompertz Quartet along with violinists Richard Gompertz, Haydn Inwards and cellist Charles Ould from 1888 to 1903, and a member of the Covent Garden Opera Orchestra from 1900 to 1903.