'The vain speculation disillusioned by the sense': The Italian painter Agostino Scilla (1629-1700) called 'The Discoloured', and the correct interpretation of fossils as 'lithified organisms' that once lived in the sea

The search for the true nature and origin of fossils gave rise, starting about the beginning of the sixteenth century and throughout the seventeenth century, to a heated debate between the supporters of the inorganic nature of these objects and proponents of an interpretation of fossils as ex-vivi. Among the latter, a key figure is the Italian painter Agostino Scilla (1629–1700), who represents one of the first naturalists who was able to accumulate substantial evidence to support the interpretation of fossils as once-living marine organisms. The world view of Scilla and his real contribution to paleontology are here analysed and contextualised, taking into account the state of knowledge characterising the time of his activities. Scilla was not only a pioneer in the field of paleontology, but he prepared the groundwork for the achievement of milestone geological concepts such as actualism, taphonomy and recognition of internal and external moulds (in the instance of nonrepresentation of original hard parts); Scilla deserves further recognition