Bill Viola’s two altarpieces for St Paul’s have had a long gestation. The idea of commissioning a pair of works for the cathedral’s quire aisles was first conceived during the artist’s National Gallery exhibition, “The Passions”, in 2003, but the first of the two, Martyrs (Earth, Air, Fire, Water) was not installed until 2014 and the second, Mary, was only unveiled last month on the feast of the Nativity of the Blessed Virgin Mary.

The American video artist, who has made a name for elevating digital to the status of high art, has a busy schedule, but that was not the only reason for the delay. Despite having had work displayed in churches from Durham Cathedral to Milan’s Basilica di San Marco, Viola makes no secret of the fact that his religious sympathies lie more with Zen Buddhism, Islamic Sufism and Christian mysticism than with biblical literalism. But it was precisely because of the universality of his themes, reflecting “our shared experience of being human” – in the words of the Revd Mark Oakley, Canon Chancellor of St Paul’s – that his work was considered ideal for the cathedral’s multicultural audience.