sentences:  The dark hemisphere was later named Cassini Regio in his honor.Iapetus is named after the Titan Iapetus from Greek mythology.The name was suggested by John Herschel (son of William Herschel, discoverer of Mimas and Enceladus) in his 1847 publication "Results of Astronomical Observations made at the Cape of Good Hope", in which he advocated naming the moons of Saturn after the Titans, brothers and sisters of the Titan Cronus (whom the Romans equated with their god Saturn).