What makes Cruel Sister by Pentangle notable?

'Cruel Sister' is notable for its ambitious arrangements and sophisticated musicianship, receiving critical acclaim upon release and solidifying Pentangle's influence on contemporary folk music. The album's title track became a staple in folk music circles and has been covered by numerous artists, showcasing its lasting impact on the genre. Released on November 27, 1970, 'Cruel Sister' was Pentangle's fourth studio album during a period of significant acclaim following their self-titled debut in 1969. The band had established themselves as pioneers in the folk rock genre, integrating various musical styles while maintaining an authentic acoustic feel, positioning them at the forefront of the British folk revival.