Discoverer of the four largest moons of Jupiter (7)
I believe the answer is:
galileo
(Other definitions for galileo that I've seen before include "US unmanned space-craft launched in 1989 to investigate Jupiter" , "It. C 16 to 17 astronomer" , "He said Eppur si muove (But it does move)" , "victim of Inquisition" , "Refracting telescope inventor" .)