The figure is clearly identifiable as a pope from his clothing . It seems trapped and isolated within the outlines of an abstract three @-@ dimensional glass cage . This framing device , described by Sylvester as a " space @-@ frame " , was to feature heavily throughout the artist 's career . A cord hangs from the upper edge of the glass case , falling just in front of the pope 's face and partially covering his eyes . It is too indistinctly drawn to identify with certainty , but given the presence of similar objects in Bacon 's later works , may be either the end of a hanging light switch or the tassel of a curtain ; the hanging cord was to become a signature for the artist . Apart from its symbolic meaning , it has a compositional function , framing the painting with a further set of vertical lines . Such an object reappears most prominently in the centre panel of his 1973 Triptych , May – June 1973 , where it is clearly a dangling light bulb . For Bacon , these elements were intended to make the figure waver in and out of sight for the viewer , alluding to the fact that bulbs can be on or off , curtains open or closed .