Kate McGarrigle, who died on 18 January, 2010, aged 63, was one half of a sisterly folk duo who found fame in the 1970s with mournful ballads.

She sang with her sister Anna and they recorded a string of albums that surprised many with their popular success.

She was also the mother of another pair of singing siblings, Rufus and Martha Wainwright (from her marriage to songwriter Loudon Wainwright III), whose success with idiosyncratic music in their respective careers mirrored their mother’s.

She was born in Quebec, Canada to a violinist mother and pianist father. She was taught piano by local nuns and became proficient in various stringed instruments during his youth. She began performing with Anna while they were both studying at university in Montreal.

They moved to New York, the folk revival capital of the world, at the turn of the decade. Kate met Loudon there and they were married in 1971 as their respective careers took off, though they would divorce before the decade was out.

Kate and Anna McGarrigle’s music proved difficult to classify for record executives, with a broad melancholic streak but also pop appeal.

They never courted commercial success, but seemed to achieve it all the same, along with the critical acclaim heaped on records such their self-titled debut of 1975 (Melody Maker’s ‘Album of the Year’) and the French language record Entre la Jeunesse et la Sagesse (1980).

British folk-influenced artists such as Kirsty McColl and Billy Bragg covered their songs, as have Irish band The Corrs and several influential American acts.

The duo continued to record into the ’90s and remained popular for the live performances, wonderfully informal affairs devoid of any showbiz pretentions. Kate also frequently joined her children on stage and was the subject of Rufus Wainwright’s heartfelt ode Beauty Mark.

She was diagnosed with cancer in 2007 and during her struggle she founded a charity to help combat the disease.