Although a doctor, Zacut was famous for his works in astronomy, namely contributions to observational astronomy, astronomical tables, and our knowledge of astronomy in Spain. Zacut came from a Jewish family originally from France; evidence indicates that he was born in Salamanca, and spent his early years there as a pupil of Isaac Aboab. Zacut had relationships with several notable figures: Don Juan de Zúñiga (the last Master of the Order of Alcántara), and the bishop of Salamanca, Gonzalo de Vivero, to whom he dedicated his most famous astronomical work La Compilación Magna. When the Bishop Vivero died in 1480, Zacut moved to the court of Don Juan de Zúñiga for whom he produced the following works: Tratado breve de las influencias del cielo and De los eclipses del sol y la luna. Zacut was in Lisbon on 9 June 1493 (working for Juan II of Portugal). He also worked for the brother of King Manuel I, who is said to have sought Zacut’s advice for Vasco de Gama’s trip around Africa (Zacut gave a favorable opinion). In 1496 when the Jews were expelled from Portugal, Zacut moved to Tunisia; he lived in Carthage for several months. He eventually moved to Ottoman lands and died in Damascus, probably in 1515 although a death date of 1522 has also been suggested. Juan de Salaya (professor of astrology the University of Salamanca from 1464 to 1469), translated Zacut’s work titled La Compilación Magna from Hebrew into Spanish. The Latin translation, known as Almanach Perpetuum, was made by José Vizinho and first published in Leira in 1496; there also exists another Spanish version of this work. It was important for the development of Spanish and Portuguese navigation at the end of the 15th century. [Cirilo Flórez Miguel]