Complex sentence: Sometime in the 1960s, Heath drew two pieces of commercial art that became familiar bits of Americana after gracing the back covers of countless comic books through the early 1970s: advertisements for toy soldier sets, they depicted Roman and Revolutionary War battle scenes.
Split into simpler sentences: Sometime in the 1960s, Heath drew two pieces of commercial art that became familiar bits of Americana after gracing the back covers of countless comic books through the early 1970s. Advertisements for toy soldier sets, they depicted Roman and Revolutionary War battle scenes.