TEE PREDECESSORS OF COPERNICUS. 339 



accurate tables to replace those constructed for Alphonso the Wise, 

 which no longer served to predict eclipses or to account for the con- 

 figurations of the planets.* Errors of a couple of hours in the pre- 

 dicted time of a lunar eclipse were noted, and Mars was two degrees 

 away from its calculated place. 



In the work of observation and calculation he gained an invaluable 

 coadjutor in Johann Miiller, of Konigsberg, a village of Franconia, 

 one of his pupils. Miiller called himself, after the fashion of the 

 time, Johannes de Monteregio, but is known to us as Eegiomontanus. 

 Together they studied the works of Ptolemy, and together they ob- 

 served the planets with the best instruments they could construct, 

 though their apparatus was much inferior to that of the Arabs. Like 

 all men of their time they were believers in judicial astrology, and their 

 tables were arranged to meet the wants of this pseudo-science. At 

 the same time astronomy benefited by their investigations, which 

 began to be based on actual observation of the sky. 



The Papal Nuncio in Vienna was then Cardinal Bessarion, once 

 Bishop of Nicaea in the Greek, now high in power in the Latin Church 

 and a friend of learning. Purbach's enthusiasm for the works of 

 Ptolemy was shared by the cardinal, and they planned a new edition 

 of his writings. For such an edition it was necessary to collect Greek 

 manuscripts. After the death of Purbach (1461) Eegiomontanus 

 went to Italy in the cardinal's suite for this purpose (1462). Here 

 he remained some seven years, collecting manuscripts, mastering the 

 Greek language, studying the sciences, and writing his treatise on 

 trigonometry. His text of Ptolemy was printed at Basel in 1538 and 

 was used by Copernicus. 



In 1471 he was settled in Nuremberg near the printing presses that 

 had been installed a few years earlier. Here he had the fortune to 

 meet a wealthy amateur, Bernhard Walther (1430-1504), who built 

 an observatory for their joint use, and aided him in his publication 

 of various writings, his ovm and Purbach's. The Ephemerides of 

 Eegiomontanus made him famous. They were the nautical almanacs 

 of those days, and were used by Columbus and Vasco da Gama in their 

 voyages of discovery. He is also the inventor of the method of lunar 

 distances for determining the longitude at sea. He was invited to 

 Eome by the Pope in 1475 to reform the calendar and there died in 

 1476. 



There is a legend that Eegiomontanus was assassinated by the sons 

 of George of Trebizond, the first translator of the Almagest of Ptolemy 

 from the Greek, because of strictures passed upon it. The legend 



* This great collection of tables was calculated in the middle of the thir- 

 teenth century by Arabian and Jewish astronomers, under the patronage of the 

 king, on the system of Ptolemy with some changes. The Libros del Saber were 

 an encyclopedia of all the astronomical knowledge of the time and are invalu- 

 able to the historian. 



