Parry was born on this day in 1848. We remember him for Jerusalem, set to the poem by William Blake, which has become England's unofficial anthem.
After he escaped a job in insurance, taken at his father's behest, Parry went to work for George Grove and contributed to Grove's massive Dictionary of Music and Musicians. He was a musical genius, and by 1883 he was professor of composition and musical history at the Royal College of Music.
"Edward Elgar learned much of his craft from Parry's articles in Grove's Dictionary. Among those who studied under Parry at the Royal College were Ralph Vaughan Williams, Gustav Holst, Frank Bridge and John Ireland" (Wiki). That's an extraordinary roster of British musicians. Teaching them, Parry had less time to write music, but if he had only written Jerusalem, it would be enough.