Francis Bacon - Study of a Bull (1991)

It could be a bull backing in to a burning, black void or one escaping it, moving hopefully into the heavenly light. What seems certain is that this final, extraordinary painting by Francis Bacon, unseen and undocumented until now, is by an artist who knows he will soon die.

The art historian Martin Harrison on Tuesday revealed Bacons final completed painting a work that has never been publicly seen, reproduced, discussed or written about. Residing in a very private, private collection in...