An article from this April discusses a house in England in which a series of tunnels were recently found by archaeologists.  The tunnels connect to a drainage system outside the house, and so they theorize that it was part of a septic system.Archaeologists to probe newly-discovered tunnelsI was unaware that such drainage systems would be found in medieval buildings.  My understanding was that such systems were only developed a few hundred years later.  Am I wrong?  Were underground septic systems being used in the Middle Ages as well?