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Associated with the frontier city of Dara and dated to around 560 CE, this late Roman/Byzantine dam is famous because Procopius described it as crescent-shaped, making it the earliest textual explanation of arch-dam behavior. Modern fieldwork has raised doubts about whether the surviving remains were truly an arch dam) or instead a gravity dam, so the site is notable both for its engineering history and for the unresolved interpretation. It remains a rare pre-modern large dam site tied directly to Justinian I's building program.