Egyptian medical papyri date the Santorini eruption, and reconcile the hitherto perceived dichotomy between archaeological/historical and scientific data. The medical documentation describes ailments, which can only have arisen from a volcanic source: ash fallout, rain acidified by ash, and a plume. Furthermore, the Egypt described by the medical texts matches the one in the series of so-called biblical plagues. This match in turn provides the length of time, 19 months, between the initial and final phases of the eruption, each phase contributing to the otherwise odd accumulation of sulfates spread over two consecutive biennia (1603-1600 BC) in Greenland's ice core. As a result, the initial phase of the eruption can be dated to August 21, 1603 BC, and the final one to March 1601 BC, in full agreement with the radiocarbon data (1627-1600 BC) based on the outermost ring on the branch of an olive tree killed by the eruption.