Complex sentence: Revolutionary War veteran Daniel Shays led four thousand rebels (called Shaysites) in an uprising against perceived economic and civil rights injustices, eventually marching on the United States' Armory at Springfield in an unsuccessful attempt to seize its weaponry and overthrow the government.
Split into simpler sentences: Revolutionary War veteran Daniel Shays led four thousand rebels (called Shaysites) in an uprising against perceived economic and civil rights injustices. Ultimately, the rebels marched on the United States' Armory at Springfield in an unsuccessful attempt to seize its weaponry and overthrow the government.