
Interior Wall, Romsey Abbey
Stone buildings and stonemasons went together in the Middle Ages. It took skill and ingenuity to produce beautiful buildings, many of which have stood for centuries. It also took planning and the use of sophisticated lifting equipment.
Stone was an expensive material to use, even if it was quarried locally, and it needed skilled men to cut and shape it.
Different groups of men worked with the stone needed for a castle, a cathedral or a church. The stone had to be quarried first. Quarrymen were not masons. Their job was simply to get the stone for the masons to work on out of the ground. Usually, local stone was used, but occasionally stone could travel long distances, even from other countries. For Winchester Castle, for example, stone was brought from Selborne (18 miles away), the Isle of Wight (30 miles, but half of them on water), Haslebury (70 miles) and Caen (across the Channel in France). Transport costs, as well as the quality of the stone, meant that stone brought from far away was very expensive.
There were different classes of masons and the first two were the rough masons and the freemasons. The rough masons were unskilled and made the rubble walls, which were often used where neither strength nor appearance was considered important. Rubble was a low grade of stone, which could not be cut or shaped. Sometimes rubble walls were dressed so that an inner core of rubble was covered with smoothly-cut and close-fitting stones. This photograph shows a rubble interior.

Arrow Slit, Arundel Tower, Southampton
Freemasons could cut freestone to make squared blocks (ashlars) or complex shapes. The interior and exterior walls of Romsey Abbey pictured at the top of the post and below are made of cut stone. The freemasons put the stones in place and carved the decorative parts of a building. Freemasons earned more than rough masons, but they were not at the top of the chain.

Exterior Wall, Romsey Abbey
The master mason was in overall charge of the building site. He was the designer, engineer and contractor. He was the man employed by the patron to be responsible for all the building work. There would be a contract between the master mason and the patron which set out what the master mason was to build and how much he would be paid for doing so. He designed the building and took on all the men he needed to get the job done. He was paid by the patron and he, in turn, paid all the other men employed on the building site.
Some patrons wanted more of a say in the design than others and some master masons seem to have reused design elements from one building to another. They might even have been employed specifically to incorporate something that they had done elsewhere and that the patron liked.
Designs for decorative work were illustrated on a tracing floor. This was a plaster-covered surface on the ground onto which the master mason could trace the full-size design. From this he made a wooden template for the freemason to use as a pattern.
The masons worked in a lodge – a wooden structure on the building site that provided some shelter while they worked on the stone. It was also a place for them to eat and rest.
The cut stones were heavy. At ground level they could be moved on wooden rollers, but getting them to the tops of ever-growing walls required more ingenuity. A pulley was used to lift stones. Usually, this was done with the help of one or more men inside a treadmill. A hand winch could be used for small blocks of stone.
Most buildings were designed using squares and circles. The master mason used simple geometry to work out the proportions with a compass and a square. He did not necessarily need to understand the mathematics behind his design.
The working season was usually from the feast of the Purification of the Virgin, or Candlemas (2nd February), to All Saints Day (1st November). At the end of the season the work was covered, often with straw, to protect it from the elements until the next season. Work stopped before temperatures fell below freezing, as the mortar was useless once it had frozen.
Medieval building techniques can be seen at the archaeological project at Guédelon, where a castle is being built using techniques from the thirteenth century. The DVD Secrets of the Castle, which was filmed there, shows these techniques.