501st Legion (MHJ)

The 501st Legion was an elite military and naval division of the Grand Army of the Galactic Republic within the Republic Military branch led by Jedi Knight Anakin Skywalker and Clone Captain CT-7567 "Rex". The clone troopers in it had dark blue markings on their armor.

Biography
What might be the most well-known Legion in all of Star Wars took place in MANY major battles extending many eras. These era extended from the beginning of the Clone Wars to the end of the Empire.