Reddit reviews Cathedral, Forge and Waterwheel: Technology and Invention in the Middle Ages (Medieval Life)

Would you consider doing a whole series on fortified bridges? I'm reading a book about medieval technology (Cathedral, Forge, And Waterwheel) and the author talks a little bit about fortified bridges, but not enough to sate my curiosity. There's a neat mention in here, if I can quote:

>As early as the sixth century, supplemental roles were found for bridges. One important one was conceived during the siege of Rome by the Goths in 537, when the enemy shut off the aqueducts whose water drove the city's gristmills. Belisarius, the Byzantine general defending the city, ordered floating mills installed close to the Tiber bridges, whose piers constricted and accelerated the current. Two rows of boats were anchored with waterwheels suspended between them. The arrangement worked so well that cities all over Europe were soon copying it. The Grand Pont in Paris, probably a combination of wood and stone, built water mills under its roadway and houses on top of it, inaugurating one of the Middle Ages' most picturesque architectural fashions.