¶ For medieval Catholic theologians, limbo – often conflated with purgatory, an overheated waiting room processing souls with chequered pasts – was a place for the church to dump bodies that did not carry the correct paperwork. (In a letter written to his fictional friend Malcolm, C. S. Lewis described purgatory as an astringent mouthwash to be drunk after ‘the tooth of life is drawn and I am “coming round.”’) The name applied to two zones: limbus patrum (Limbo of the Fathers), and limbus infantum (Limbo of Infants). Limbo of the Fathers existed on the fringes of Hell and was a place reserved for men who had died before Jesus Christ lived. Where the old prophets waited in unfinished happiness was a restricted ward, but not a penal confinement. In his fifteenth-century painting Christ in Limbo Fra Angelico depicted limbo as a dark and cool cave. A simple, classical arch has been carved at its mouth, as if the entrance to a secret system of passages drilled deep inside a mountain. A century later, a follower of Hieronymous Bosch dumped limbo on the bank of the River Styx, beneath an acrid smoke-filled sky – souls huddled together beneath the entrance to a light-filled tunnel where Christ is to rescue them. In the fourth canto of his Inferno, Dante Alighieri – writing in exile from his home town of Florence – describes limbo as a twilight grove where those who were without sin but who had ‘lived before the Christian age’ waited patiently until Christ descended to the underworld for the Harrowing of Hell, liberating them to enter Heaven. ‘Here in the dark (where only hearing told),’ writes Dante, ‘there were no tears, no weeping, only sighs / that caused a trembling in the eternal air – / sighs drawn from sorrowing, although no pain.’ Gustave Doré, illustrating The Divine Comedy in the 1860s, stayed close to Dante’s vision, depicting limbo as woodland frozen in crisp, monochrome moonlight. Dante’s guide, Virgil, points out Old Testament saints: Abel, Noah, Abraham, David, Rachel. Walking amongst the trees they see the pagans Homer, Horace, Ovid and Lucan, amongst others. On a ‘verdant lawn’ Dante and Virgil meet the Greeks – Socrates, Plato, Euclid, Hippocrates, Zeno – the Muslim philosophers Avicenna and Averro