In this 1951 masterpiece he reaches into the past to capture the anguish of the present. Yet Bacon, a gay man before the reforms of the 1960s, always saw the mainstream with an outsider’s irony.

Avant-garde art had always rejected traditional themes. It took a gambler and drinker to turn modern art on its head. The bloody spoils seem like a trophy, and are more chilling for it. The culture clash that underpinned Cranach’s art – German courtly splendour and strait-laced religious reformation – powers a magnetic imagining of Jewish heroine Judith displaying the head of Assyrian general Holofernes. Lucas Cranach the Elder – Judith With the Head of Holofernes Photograph: Peter Cavanagh/Alamy Scotlandġ. Judith With the Head of Holofernes by Lucas Cranach.