A large wheel walked from inside by one or two men drove a windlass and rope, lifting stone blocks of two to three tonnes. Reintroduced in western Europe from about 1225 — the first archival reference to a magna rola is French, followed by a manuscript image around 1240 — it was mounted on scaffolds and later inside roof spaces, moving upward with the fabric as the building rose. Harbour versions were fixed in timber or masonry towers to transfer cargo between ship and quay. Around it grew the organised building site: the masons' lodge, templates, banker masons and seasonal campaigns.
Lifting capacity, not stone strength, set the practical height of medieval construction; the treadwheel made the 30 to 40 m Gothic nave and its towers buildable and financeable in phases. The same machines fixed on quays defined the working edge of Hanseatic and Flemish ports. The organisation of labour and templates around the lifting machine is the ancestor of modern site management.
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