The ancient text considered a foundational work in Western philosophy is Plato's "The Republic." Written around 380 BC, it explores justice, the ideal state, and the philosopher-king concept. Through dialogues featuring various characters, including Socrates, Plato examines the nature of justice, the role of the individual in society, and the structure of an ideal state. "The Republic" has profoundly influenced Western political thought, ethics, and philosophical inquiry, making it a cornerstone of philosophical discourse throughout history.