Building a medieval castle was a massive feat of engineering and logistics that began with leveling a site and digging deep foundation trenches. These trenches were filled with a rubble and mortar mixture (quicklime and sand) to create a stable base. Construction utilized two types of masonry: "rubble" (irregular stones for the core) and "ashlar" (smooth, precisely cut stone for the exterior). Master Masons designed full-size templates on plaster floors, which stone cutters used to carve blocks. To lift these heavy stones, builders used wooden cranes, pulleys, and "treadwheel" winches. Early castles often started as "motte-and-bailey" structures made of earth and timber before being upgraded to stone. Because lime mortar sets very slowly and can be washed away by rain, construction was largely seasonal—pausing during the wet winter months—meaning a single fortress could take a decade or more to complete.