Although various sources list Theodor Vercruys as a Dutch artist, his activity was confined, as far as is known, to Italy, notably Florence. Although he was mentioned in lexicons of artists as early as the 18th century, as time passed he was increasingly confused with the German artist Dietrich Crüger and gradually sank into oblivion. Consultation of various sources, some of them unpublished, has put some flesh on the bones of his biography. Transcriptions of two hitherto unpublished relevant sources are to be found in the appendices. In Florence, Vercruys played an important part in the production of a large series of prints after paintings in the Medici collection. He was also active as a book illustrator and made original drawings and prints. The list of his drawings is extended in the article to fifteen, eight of which are in the English royal collection (as anonymous). Doubts are cast on the authenticity of three drawings assigned to the artist, and three others are de-attributed. Although Theodor Vercruys was not one of the great 18th-century artists, his work does seem to have been much appreciated by his contemporaries. His versatility as an engraver, draughtsman and probably also a painter, and the unmistakable Netherlandish influences in his work, single him out as a wrongly neglected 'minor master' in a period of Italian art history to which relatively scant attention has been paid hitherto.