The word "lunatic" derives from the Latin "lunaticus," meaning "moonstruck." Ancient Romans believed the Moon could cause madness, especially during the full moon phase.
This belief persisted for centuries. Even in the 18th century, English law recognized "lunacy" as a temporary madness caused by the Moon's phases, and people could be acquitted of crimes if they occurred during a full moon.
While modern science doesn't support moon-induced madness, the term reminds us how deeply lunar beliefs were embedded in human culture.