Short answers, pulled from the story.
Edward Elgar was an English composer, born on the 2nd of June 1857 and died on the 23rd of February 1934. He is best known for the Enigma Variations, the Pomp and Circumstance Marches, his violin and cello concertos, two symphonies, and the choral work The Dream of Gerontius.
Elgar felt himself an outsider on several counts. He was a self-taught composer in circles dominated by academics, a Roman Catholic in Protestant Britain, and acutely sensitive about his humble origins as a piano tuner's son even after he achieved recognition.
The enigma is an overarching theme that Elgar said "runs through and over the whole set" but is never actually heard. Though there are fourteen variations on the original theme, this hidden theme was never identified by Elgar. He premiered the Variations in 1899 under conductor Hans Richter.
Land of Hope and Glory came from the trio of the first Pomp and Circumstance March. The contralto Clara Butt persuaded Elgar that words could be fitted to it, and A. C. Benson supplied them. It became immensely popular and is now considered an unofficial British national anthem.
Alice Elgar, born Caroline Alice Roberts, was the daughter of Major-General Sir Henry Roberts and Elgar's wife from the 8th of May 1889. She acted as his business manager, social secretary and musical critic, and was disinherited by her family for marrying him. She died on the 7th of April 1920.
Elgar's music was identified with the Edwardian era, and after the First World War he no longer seemed a progressive composer. His stock remained low for a generation after his death in 1934, beginning to revive significantly in the 1960s with the help of new recordings.