Artist Bill Viola explains the uncanny origins of his major work, Five Angels for the Millennium, now at Tate Modern

A pioneer of film and video art since the early 1970s, Bill Viola employs both sound and image to profound effect. In Five Angels for the Millennium (2001), five individual video sequences (Birth Angel; Fire Angel; Ascending Angel; Creation Angel; and Departing Angel, pictured) are projected directly onto the walls of a darkened gallery.

'Five Angels came out of a three day shoot in Long Beach that I had undertaken for several other projects. All I knew was that I wanted to film a man plunging into water, sinking down, below, out of frame - drowning. 'A year or so later, going through this old footage, I came across five shots of this figure and started working with them - intuitively and without a conscious plan. I became completely absorbed by this man sinking in water, and by the sonic and physical environment I had in mind for the piece.

'When I showed the finished work to Kira [Perov], my partner, she pointed out something I had not realised until that moment: this was not a film of a drowning man. Somehow, I had unconsciously run time backwards in the five films, so all but one of the figures rush upwards and out of the water. I had inadvertently created images of ascension, from death to birth.' Bill Viola, 3 June 2003