Masons’ Marks Talk by Iain Ross Wallace MA

Notes from the on-line Talk on Mason’s Marks given by Iain Ross Wallace MA for Dundonald Castle on 10th June 2021

Written by Gwen Sinclair

Ever since the fictitious murder of Louvre’s beloved curator, Jacques Saunière on whose body the Prefecture de Paris found a grisly carving of a disconcerting cipher, leading to a hunt for ancient symbols to find the killer, Dan Brown’s Da Vinci Code has arguably inspired the world to take a closer look at marks and symbols which have long-since outlived their signatories.

This month’s online talk for Friends of Dundonald Castle (SCIO31541) was given by Iain Ross Wallace MA MRes FSA Scot who presented a thoroughly fascinating report outlining some of the findings from his Post Graduate Research undertaken at the Department of Archaeology at the University of Glasgow entitled Leaving a Mark on History. This was a unique and detailed study of mason’s marks found on a selection of medieval stone buildings in central and southern Scotland from the 12th and 13th Centuries. Links to read Iain’s thesis can be found in the closing notes below.

Iain was inspired to investigate these marks after a visit to Crookston Castle – thought to be the second oldest building in Glasgow – situated on the top of a hog-backed knoll above Leven Water – where this medieval tower house contains so many visible mason’s marks, Iain was duly inspired to make them the subject of his Research Masters thesis to find out more!

“Much has been done already to record the medieval masons’ marks; but there is crying need for some scholar with sufficient leisure to assimilate these scattered records and work out a full synthesis.” (Coulton 1928, 143) 1

What are Mason’s Marks?Mason’s Marks are a sequence of lines cut into the face of a piece of carved stone to indicate who worked that stone.”  Iain explained – and it’s from those marks, painstakingly photographed and analysed on the rendered stone work from Glasgow Cathedral, Crossraguel, Paisley, Dryburgh, Jedburgh, Kelso and Melrose Abbeys, as well as Bothwell Castle and Dirleton Castle, he sought to find out more. By exploring what these chiselled marks and symbols might mean, looking for any connections between them, and where they were located within these medieval buildings, Iain’s research led to establishing that these marks are the main, if not the only source of information we have about the artisans who cut, carved and dressed every single piece of stone contributing to the construction of these early Scottish architectural masterpieces. 

Slide by Iain Ross Wallace

But what was the reason for the masons’ marks?  Iain explained that a series of simple lines and shapes, such as 5-pointed stars, or a bow-tie (as shown above) were literally cut into a stone. These and many, many other symbols served several purposes – for example, to show Quality Control – such as we might find from a clerk of works inspection these days, or Quarry Marks to indicate where the stone had come from, or as an identifying symbol – not unlike an artist’s signature – cut into the stone to show who it was that had prepared a piece of stone before it was put in place.

The stone mason was the craftsman who cut, dressed and even carved each stone ready for embedding into the structure.  The symbols they left were likely to have been a language all of there own as Iain explained: one reason for the necessity for these marks was that 99% of the population couldn’t read, and so relied upon symbols such as these to convey a message. And so these marks and lines would likely have been well known to those involved in the building trade at the time.

As for the symbols themselves, and what they might mean, the most important point to note is the they were made of simple strokes cut into stone which would not have taken too much time or effort to create.  Iain’s research has led to connecting many of the inscribed marks discovered in his research to that of the fairly simple symbols from Elder Futhark (German 2nd-8th Century) or Younger Futhark (8th Century Scandinavian and Scottish) runic alphabets. They may well have been the initials of someone’s name, for example if we note the letter ‘d’ in ‘Elder Futhark’ – it looks similar to the bow-tie shape as noted earlier, which has been commonly found in the buildings which were studied. 

Slide by Iain Ross Wallace

As for the social history of the era, Iain has found that the distribution of these marks geographically can somewhat identify work patterns of individual masons – where the same marks have been found on several different structures – as noted on the slide below. However it seems difficult to date the building work based on mason’s marks alone since different parts of a building were completed at different times. Iain explained that a huge amount of data has been analysed in an attempt to identify the number of repeated marks in these buildings.  This has helped to show the shear number of workers involved in one structure.  For example at Glasgow Cathedral some 452 different mason’s marks had been made between 1136 and 1500 – outlining not only the scale of the work force, but also the time taken to complete the task. Masons’ marks in the lower church alone indicate that 250 different masons worked on it between 1136 and 1290. 

Iain’s research also suggests that a whole career could be spent on one building.  Furthermore, he observed slight variations of a mason’s mark – with the addition of a notch, for example,  being added to a existing mark, which could well have been an modification of a father’s, or even grandfather’s mason’s mark, since a son, who followed his father into the profession would need his own mason’s mark, and it looks as though some have been modified from an established mark in order to ensure a continuation of a known family’s symbol. 

Slide by Iain Ross Wallace

Master Masons were responsible for leading the building work, as well as paying and instructing their young apprentices – who would begin training at around the age of 10, with their apprenticeships lasting until they were around 17 years of age. Work as a mason would then likely continue for the rest of their lives. Iain explained that Master Masons would be paid by the prepared stone – usually finishing 6-7 stones per day, with 9 or 10 old pennies per day as payment. From payment, a Master Mason would have had to buy his tools, pay his labourers and any apprentices. Iain explained too that elaborate stone-cutting and carving would pay more – such as is likely with special pieces of stone such as the Dean’s Chair at Glasgow Cathedral, which, after the altar, would have been considered the most eminent piece of stone-cutting craftsmanship in the whole building.  Iain observed too that The Dean’s Chair at Glasgow Cathedral has 3 different marks on the same stone, indicating that 3 different masons – most likely the marks of Master Masons – had worked on this important part of the building – as shown below.

Slide by Iain Ross Wallace

At Dundonald Castle, Iain hopes to return soon to further investigate the many mason’s marks to be found here, as a follow-on from the community survey which happened in 2016 – with the enthusiastic assistance of Dundonald Primary School pupils who provided drawings and notations for all the marks that they spotted on the interior and exterior castle walls!  Iain is certain that this early investigation was literally just scraping the surface of what’s to come, and hopes to return to do a rigorous and detailed survey of what is to be found on the walls of Dundonald Castle.  We can’t wait to find out what might be discovered about the masons who built it! 

Some of the Mason’s Marks found at Dundonald Castle. Slide by Iain Ross Wallace

Iain concluded that he is hopeful that his research will provide a foundation for future similar investigations across Scotland in order to build a wider picture of the movements and trends of medieval masons.  It’s fair to say that finding out more about this subject has inspired in me further awe of the huge amount of work and skill which has gone into the forming of these great castles and abbeys. They are in themselves monuments to their almost completely unknown creators whose endurance produced these superstructures on the Scottish landscape, and which continue to serve and enrich Scotland’s culture to this day.

Perhaps these masons marks or simple lines carved by the sharp end of a chisel were once covered by plaster or by tapestries to help defuse the winter chills, but now as time has past, they are once again revealed for all to see – as a strange irony that these mason’s marks have outlived it all. But perhaps that was the point!

Glasgow Cathedral Choir by © User:Colin / Wikimedia Commons, CC BY-SA 4.0,

As ever there were good questions from the audience, and once again thank you to everyone who attended, and to Iain for taking the time to share his fascinating findings with us in this highly enjoyable and informative evening.

If you missed this talk, it’s available for Member’s of Friends of Dundonald Castle (SCIO ) to watch again on our website. Membership starts from £10 per year, and includes newsletters, free entry into the castle, first notification of events such as this, with all funds raised going to help us to further our work at Dundonald Castle. Find out more: 

The next exciting on-line talk will take place soon and will be given by David Harkin who works within the Conservation Directorate at Historic Environment Scotland. David will be looking in detail at the impact climate change has on historic buildings – keep an eye on our social media to book your front row seat – same time, same place – we look forward to seeing you there!

Lastly, as always, do feel free to contact us with any questions you have on this subject, and we will do all we can to help to answer them, or if you have any subjects which you would like us to cover in our Monthly Talks Series, again do get in touch. 

Read Ian Ross Wallace’s Thesis ‘Leaving a Mark on History’:

Write your name in Elder Futhark and Younger Futhark runes:


1Quote borrowed from Ian Ross Wallace 2020:  ‘Leaving a Mark on History’ Chapter 1, p1.


Cover Image: Dundonald Castle Pit Prison Mason’s Mark by Gwen Sinclair

Slides by Iain Ross Wallace

Glasgow Cathedral by © User:Colin / Wikimedia Commons, CC BY-SA 4.0,