Galileo did not discover rings. He discovered the four largest moons of Jupiter, which he called the "Medicean stars" in honor of his patron, Cosimo de' Medici.

The rings of Saturn were first observed by Galileo in 1610, but he did not recognize them as rings. He described them as "ears" or "handles" on either side of the planet. It wasn't until 1655 that Christiaan Huygens correctly identified them as rings.