Complex sentence: Europa, along with Jupiter's three other large moons, Io, Ganymede, and Callisto, was discovered by Galileo Galilei on 8 January 1610, and possibly independently by Simon Marius.
Split into simpler sentences: Europa, along with Jupiter's three other largest moons, Io, Ganymede, and Callisto, was discovered by Galileo Galilei in January 1610. Europa itself was discovered on 8 January 1610 by Galileo Galilei, and possibly independently by Simon Marius.