British chorister William Petter turned to composition after being diagnosed in 2013 with a life-threatening disease, clear-cell sarcoma. Friends and associates organized a recording of Petter's works, in which Petter himself participated for as long as he was able. The recording, benefiting the organization Sarcoma UK, reached top British chart levels after the composer's death. Petter was born in 1982. His parents were both musicians, and the family moved to Oxford in 1987. Petter was accepted into the New College Choir and its top-notch program for boy choristers. In addition to singing, he studied piano, organ, violin, guitar, and composition. Petter majored in neuroscience at the University College London but kept a hand in music as a member of the student opera chorus, and he switched back to music for a graduate recital diploma degree (DipRAM) at the Royal Academy of Music. For some years Petter worked as a freelance musician in London, often singing with top choirs such as those of Westminster Cathedral and Westminster Abbey, as well as the enormously popular The Sixteen. Petter also was a solo vocal recitalist, performing music from Bach to song of the 20th century. He co-founded the Oxford Bach Ensemble, a mixed professional-amateur group that has specialized in performances aimed at raising money for charity. Petter also taught singing and directed several choirs. After his diagnosis, Petter resolved to remain as active as possible. He turned in earnest to composing, writing two mass settings and a variety of smaller works. His style was tonal but original and direct in unusual ways, drawing on his lifetime of experience performing in choirs. Petter participated in organizing Ablaze with Light, a recording of his works, but was unable to direct it as planned. Petter died on October 10, 2016, a month after his 34th birthday. He married and was survived by a daughter, Rose, for whom the Rose Singers, the performers on Ablaze with Light, were named.