Medieval illustration depicting Richard of Wallingford (1292-1336), an English mathematician who made major contributions to astronomy, astrology and horology while serving as abbot of St Albans Abbey. He is best known for the astronomical clock he designed, while he was abbot, which is described in the Tractatus Horologii Astronomici (1327). Richard suffered from leprosy, which explains the pockmarked appearance of his face in this artwork.