When we picture the Knights Templar, we summon white mantles, red crosses, and distant Crusader citadels. Rarely do we imagine them stooped over a sluice gate, calculating the fall of water across a millpond. Yet behind the warrior-monk stood a quieter figure: the hydraulic engineer. What did the Templars actually build with water?
A medieval estate near Rotterdam, the Netherlands, called De Tempel has disappeared entirely. But its name, its extraordinary legal privileges, and its possible links to the Knights Templar continue to provoke questions that eight centuries of scholarship have not definitively answered. Was this tiny domain merely a drainage station, or something far more remarkable: a house of the Templar Order? And what about the present estate De Tempel?
