In chapter 12 of the book of Exodus, God's final vengeance upon the Egyptians for the enslavement of the children of Israel is the death of the firstborn. Called upon to mention the incident in the pageant of Moses and Pharaoh, a writer in medieval York chose to substitute ‘grete pestelence’ for the biblical episode. This was a striking alteration to the canonical source, for in later medieval England ‘the grete pestelence’ had come to be the customary way of referring to the Black Death of 1348–9. Upon hearing the grim words, the tyrannous and verbose Rex Pharaoh is immediately deflated, capitulates and orders the release of the Israelites – in performance, a moment of chill stasis after the pell-mell black comedy with which the reports of the preceding plagues of Egypt would probably have been presented. When the pageant was new, this may also have been a moment of remembrance for survivors of the Black Death and those born in the succeeding generation, for the York Hosiers' pageant of Moses and Pharaoh was probably composed when the memory of this, the most destructive of all the plague's visitations, was still a living memory. The earliest possible documentary reference to the existence of a cycle of Corpus Christi pageants presented by the crafts of York dates to 1377, though our extant copy of Moses and Pharaoh was not set down until much later.