In 1610, Galileo observed the peculiar appearance of Saturn, but was not able to recognize the true shape of the features on either side of the planet. It was not until almost 50 years later that the astronomer Christian Huygens discovered that the shapes were really rings.
One obstacle to the recognition of Saturn's rings was that they are seen edge-on from Earth every 15 years, and thus seemed to disappear.
Saturn Ring Plane Crossing, 1995.
Structure In The Rings
By 1675, Jean Dominique Cassini had discovered a gap in the rings that now bears his name (the Cassini Division). Numerous other gaps and rings were discovered by Earth-based telescopes through the 1970s, so that by the time Pioneer 11 arrived in 1979, the light and dark bands had their own set of names.
Voyager 2 Image showing Cassini Division.
Pioneer 11 close-up of Saturn's ring structure.
View of Saturn's rings from the Cassini spacecraft.