Marin Getaldic – Marinus Ghetaldus (1568-1622) born in Dubrovnik, was the most outstanding Croatian scientist of his time. He studied in Italy, England and Belgium. His best results are mainly in physics, especially optics, and mathematics. Among his numerous books let us mention Promotus Archimedus (Rome, 1603) and De resolutione et compositione mathematica (Rome, 1630, in five voluminous books), in which Getaldic appears as a pioneer of algebraization of geometry.

Marinus Ghetaldus: De resolutione et compositione mathematica, Rome, 1630.
A copy kept by the National and University Library in Zagreb.

De resolutione et compositione mathematica libri qvinqvi (Rome, 1630, 343 pp., 22.5 x 31.8 cm), published eight years after his death; 
a detail from Lemma XXI; Getaldic is considered to be the main predecessor of Analytic Geometry.

His contributions to geometry had been cited by Christian Huygens and Edmond Halley.

Marin Getaldic, a portrait kept in Rector’s Palace in Dubrovnik

Getaldic is the constructor of the parabolic mirror (diameter 2/3 m), kept today in the National Maritime Museum in London. During his sojourn in Padova he met Galileo Galilei, with whom he corresponded regularly. He was a good friend to the French mathematician François Viète. The fact that the post of professor of mathematics had been offered to him in Louvain in Belgium, at that time one of the most famous university centers in Europe, proves his high scientific reputation.
A Venetian Paolo Scarpi wrote about him: In mathematics he was like a demon, and in his heart – like an angel.

• Marini Ghetaldi: Promotus Archimedus, Rome 1603 (online book provided by the Archimedus Project)
• Marin Getaldic (in Croatian)

Ferdinand Feller, the eldest brother of Vilim (William) Feller (1906-1970), is the author of the graphic sign of the Croatian optical industry Ghetaldus, named after Marinus Ghetaldus, that is, after Marin Getaldić. Photo by D.Ž. in the city of Rijeka.
See also Elsa fluid.