One of the most outstanding Dubrovnik mathematicians, physicists and astronomers of the 17th century was Stjepan Gradic (1613-1683), who was a Director of the Vatican Library. Some of his experimental results are cited by Jacob Bernoulli, and his tractate about navigation incited Gottfried Wilhem Leibniz to discuss the problem of steering ships using helms. Gradic’s book Disserationes physisco-mathematicae quatour was published in Amsterdam in 1680. He died in Rome, where according to his last wish he was buried in the Croatian church of St. Jerome.