The Stabat Mater's imagines the sufferings of the Virgin Mary at the foot of the cross, and Pergolesi's 18th-century setting remains a choral favourite.

Pam Self tells the moving story of how this piece unites her and her friend Helen Vaughan, both during life and after.

Soprano Catherine Bott reflects on the piece's themes.

The Stabat Mater has been reinterpreted many times over the years: Sasha Lazard recalls singing it in the school choir, before later taking the melody and transforming it into a dance version for her album 'The Myth of Red' rechristening it 'Stabat Mater IXXI' in the wake of the September 11th attacks.

Victor Alcantara also sang it as a boy, before returning to the piece as an adult and transforming it into a jazz opus.

Composer and Conductor Paul Spicer examines the musical tensions in the piece, likening its opening to "a heartbeat."

Professor Anthony DelDonna recalls a performance of the Stabat Mater in his hometown of Naples, and reflects on the moment which reaffirmed his his faith.

Producer: Toby Field

First broadcast on BBC Radio 4 in February 2013.