models in IAL 4: The History of Astronomy to Galileo . When the heliocentric solar system of Nicolaus Copernicus (1473--1543) was introduced, the puzzle of retrograde motion vanished. Caption: " Nicolaus Copernicus (1473--1543) portrait from Town Hall in Thorn/Torun (1580)". Yes, Copernicus had big hair. Credit/Permission: Unknown artist, but possibly based on