Born in Treforest in 1891, Morfydd Owen was the bright hope of Welsh music when she took up a place at the prestigious Royal Academy of Music. And yet she would die tragically young, following an operation conducted at the Oystermouth home of her parents-in-law. Nicola Heywood-Thomas looks at the life, the mystery and the musical legacy of Morfydd, one of whose compositions has featured in this years's BBC Proms.