Nicholas Copernicus (d. 1543) was the first person to propose a sun-centered cosmos for mathematical astronomy. But Copernicus did not cite earlier astronomers, whether from Europe or Islamic civilization, who worked within two hundred years of his own career. Leading experts on Copernicus have concluded that key aspects of Copernicus’ astronomy must have come from astronomers working in Islamic lands in the thirteenth and fourteenth centuries. This paper investigates one conduit of scientific information between the Islamic world and Renaissance Italy, a network of scholars spanning Italy, Crete and the Ottoman Empire. One of the most remarkable members of this network was Jewish scholar named Mūsā Jālīnūs. Mūsū Jālīnūs, known in Hebrew as Moshe Galeano, spent time in the Ottoman Sultan Bayezit’s court. By the first decade of the fifteenth century, Mūsā Jālīnūs had learned of important advances in astronomy, including some that later appeared in Copernicus’ work. And in the first decade of the fifteenth century, while Copernicus was at the University of Padua, Mūsā Jālīnūs traveled to nearby Venice and met prominent figures there. Not only did some of the scientific theories that Mūsā Jālīnūs described in his writings appear in Copernicus’ work but other theories that he described arose in the treatises of lesser-known Renaissance astronomers. The case of Mūsā Jālīnūs, and of the scholarly network more broadly, is an argument for not restricting oneself to the question of the transmission of Copernicus’ sources, but for thinking more broadly about connections between the lands surrounding the Eastern Mediterranean and Renaissance Europe.