New Building Technologies. Two of the most enduring images of the Middle Ages are castles and cathedrals. To construct these magnificent structures medieval building technology advanced to limits the Romans had never approached and used available materials in ways they had never imagined. Medieval builders constructed castles and cathedrals largely from cut stone and used quicklime mortar —sometimes to hold the blocks in place, but more often to fill in gaps. Their solid blocks of stone had to fit together with tolerances of less than a quarter inch (5mm). Though they could use water-powered mills for cutting stone from the quarries into uniform slabs, most of the work was still done by hand with hammer and chisel. By the thirteenth or fourteenth century, the magnificent castles and cathedrals of medieval Europe had begun to revive the "lost glory" of...