At 16 she began to study piano and composition with Dr David Evans in Cardiff and had her first published work, a hymn tune entitled "Morfydd", produced in 1909.

She provided musical examples to illustrate Lady Lewis's lectures on folk song and in 1914 they collaborated in publishing Folk-Songs Collected in Flintshire and the Vale of Clwyd.

[9] Owen knew David Lloyd George, then Secretary of State for War, who commissioned a work and chose her as the soprano soloist at the Cymanfa Ganu of the National Eisteddfod in Aberystwyth in 1916.

She also was friends with several Russian émigrés, including Prince Felix Yusupov, who had been involved in the assassination of Rasputin, and Alexis Chodak-Gregory, who proposed marriage.

In 1915 she asked for, and received, a fellowship from the University of Wales to visit Saint Petersburg to study the folk music of Russia, Norway and Finland.

[14] Towards the end of 1916 Owen was introduced to the London Welsh psychoanalyst Ernest Jones and after a brief courtship they married at Marylebone Register Office on 6 February 1917.

There were also tensions in the marriage around the role Jones expected his wife to take in supporting his busy professional and social life, inevitably at the expense of her career as a musician and output as a composer.

In the summer of 1918 the couple were holidaying in South Wales, staying at the home of Jones's father at Oystermouth near Swansea, when Owen developed an acute appendicitis.

It had recently been discovered which neither the local doctor nor I had known, that this is a likelihood with a patient who is young, has suppuration in any part of the body, and has been deprived of sugar (as war conditions had then imposed); in such circumstances only ether is permissible as an anaesthetic.

[19] Owen was buried on 11 September in Oystermouth Cemetery, on the outskirts of Swansea, where her gravestone bears the inscription, chosen by Jones from Goethe's Faust: "Das Unbeschreibliche, hier ist's getan".

[20] In 1924 Jones arranged, with the assistance of Frederick Corder, the publication of a four-volume memorial edition of selections of her orchestral and instrumental work and of her compositions for voice and piano.

[21] Thanking Jones for the copy he sent her, her close friend Elizabeth Lloyd wrote, "Each page brought fresh memories of our lost darling".

Her most well known include Slumber Song of the Madonna, To our Lady of Sorrows, Suo Gân[citation needed], and her masterpiece in Welsh, Gweddi y Pechadur ("A sinner's prayer").