VREMAN, Ivan (Ureman), (June 6, 1583, Split - April 22, 1620, Nanchang, China), mathematician, astronomer, missionary. In 1600 he entered the order of Jesuits in Rome. He studied in Rome, in Spain and Portugal. While studying at the Rome Academy he carried out astronomical observations and kept correspondence with prominent scientists. In a letter to the Italian astronomer G. A. Magini he described his observation, carried out together with prominent mathematicians and his former professors, Christophor Grienberger and Christophor Clavius, of the eclipse of the moon in the night between January 19 and 20, 1609. He observed the eclipse with the unaided eye, as the binoculars was invented in 1608 and was not yet widely used. The aim of his observation was to determine the exact time when the Moon leaves the shadow of the Earth and compare it with the data obtained on the basis of a theory. He held courses in mathematics in Oropesa (Spain) and in Lisboa, and set out to missions in India and China in 1615. On his way to China he observed the lunar eclipse, carried out systematic measurements and determined magnetic declinations, differences between European and Asian time systems, and the positions of places from Goa to Macao. He reported the obtained results in a letter dated November 20, 1616 and addressed to Christophor Grienberger in Rome. A fragment of the letter was published in 1643 by A. Kircher. From 1616 he held courses in mathematics, researched Chinese astronomy and translated reports by Japanese missionaries. Due to the persecution of Christians in China, he managed to enter the country secretly as late as the end of 1619. His interest for research in mathematics and astronomy was built into his serious, years-long preparations for missionary work in China. Due to the fact that he determined geographical coordinates of a number of places, we may consider him to be the pioneer of Croatian cartographers.