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Antiquitates Rerum Humanarum was Varro's comprehensive work on the origins of Roman customs, beliefs, and institutions. This monumental work explored the etymology of Latin words, religious rituals, and social practices, providing valuable insights into the development of Roman civilization. Varro's meticulous research and detailed analysis made Antiquitates Rerum Humanarum an indispensable resource for scholars and historians seeking to understand the foundations of Roman society.