Making leather in the Middle Ages was a dirty and smelly business, involving everything from animal dung and urine to rotting hides. Lucie Laumonier explores how medieval tanners practised their craft and why their workshops became a major source of pollution in medieval towns.
By Lucie Laumonier
Before the invention of plastic, leather was essential in a broad array of sectors. From clothing and accessories to animal harnesses and saddles, from the fabrication of tool parts, parchment, bags and pouches, to quivers and armour, the leather industry fulfilled an essential function in medieval societies. The industry itself was divided into two realms of competencies: the preparatory phase which corresponds to the transformation of hides into leather, and the manufacturing phase that corresponds to the transformation of leather into products (‘leather-working’).
The preparatory phase involved a large range of actors who belonged, in the later Middle Ages, to different guilds: skinners, leather curriers, tanners, tawyers and cordwainers. In large and populated cities, boundaries between guilds regarding their expertise were usually tightly enforced. In Chester, England, the tanners obtained an ordinance in 1362 prohibiting the cordwainers from meddling with their trade. But in smaller towns there could be a significant overlap between the workers’ activities. In what follows, I’ll walk you through the process of leather tanning and tawing, with an eye towards the environmental implications of the process. Be careful, it was a fairly gross and noxious industry!
Preparing the Hides
Ulrich Peringer, a medieval leatherworker, depicted in 1464 in the House Book of the Mendel Twelve Brothers Foundation. Nuremberg City Library, Amb. 317.2°, fol. 82v.
Leather is an animal product: it is made from the hides of bovines, ovines and caprines, as well as from wild animals, such as deer. Tanners acquired hides from butchers. In England, archaeologists have indeed found large quantities of cattle horns in tannery pits located in Tanner Street in Northampton, which show that tanners received cattle hides with the horns and hooves still attached. In Montpellier, southern France, archaeologists recovered caprine heads and feet in pits located in the tanning quarter: there too, tanners received the hides with body parts still attached. Tanners therefore had to first remove the horns and lower appendages from the hides.
Then, it was time to wash and soak the hides to clear out any blood and dung left there. A late medieval treatise discussing skin tanning and written in Bologna, Italy, recommended that the hides should soak for five days “until the flesh is well macerated,” but specified that tanners should change the water every day or two days for the bad smell coming out of it. The soaking of hides was an issue for neighbours and residents. Brewers of Colchester, England, complained c. 1425 to the town that the tanners were laying hides in the River Colne and polluting the water. In fifteenth-century Ipswich, five tanners were fined for having soaked hides in a common well, which contaminated the drinkable water.
The next step was to detach the hair and hair roots from the skin. To ease the scraping-off process, tanners used different techniques. First, they could pile up the hides in a warm atmosphere until the hair started to detach. But to hasten their work, tanners soaked or sprinkled the hides with urine, lime or ashes, depending on the techniques they preferred. The lime I refer to here is calcium hydroxide, an alkaline agent—not the fruit. An Italian author of a tanning guidebook said that certain hides should be kept soaking in lime for fifteen days, all the while lifting up the hide twice a day and letting it drip for two hours. But the statutes of the tanners of Venice, dated 1401, stipulated that hides should remain in the lime for one or two days, then removed, and then put back in the lime for one week.
Regardless of the preferred process, and once properly soaked, hides were rinsed and spread over wooden beams to be scraped with a knife on both sides. It was then time to treat the skins to remove the excess lime, extend the skins and make them flexible. Skins could be immersed in a warm infusion of bird guano or animal dung, or drenched in fermenting cereals, such as barley, in which stale beer or urine was added.
Let’s pause here for a minute. The preparatory steps of the tanning process were already noxious and highly polluting. Animal hair, blood and fat were washed downstream; hooves and horns were buried into cesspits; piles of guano and of dog dung were laying around in the leather-working district and mixed with the smell of urine and fermented cereals. These products had to be washed and replaced, while a great quantity of water was required to wash and soak hides! In thirteenth-century London, the Walbrook River that ran by the tanners’ quarter was so polluted that it had become obstructed by dung, “rotten matter” and other unsavoury refuse.
Tanning (and spillovers!)
A medieval tanner depicted in 1440 in the House Book of the Mendel Twelve Brothers Foundation. Nuremberg City Library, Amb. 317.2°, fol. 62v.
The next phase of the tanning process depended on the thickness of the hides, which were cut to the desired size. For the thickest and strongest leather, used, for instance, for shoe soles, belts or harnesses, hides were placed in pits, that is, large tanks set in the ground. Hides were arranged in horizontal layers, with layers of tanning products in between. Tanners added water to the pits to immerse all the skins properly. These were called layaway pits. After a while, tanners moved the skins to other pits filled with tanning liquor and cold water. Skins typically remained in these pits for about a year. Once satisfied with their work, tanners rinsed the skins, smoothed them over, and let them dry. But spillovers were a frequent issue. In fifteenth-century Ipswich, two tanners were accused of having kept their “barkepits” too close to a public watercourse, with the tanning liquor contaminating the stream. Because of this ongoing issue, it was decided in 1466 that tanning pits would have to be licensed and inspected by the town’s authorities to make sure their contents were not polluting any water source.
What about the tanning liquor? Boiled oak bark was used in England and Northern Europe as the main tanning agent, for it was readily available. In Southern Europe, other plants, such as sumac, tended to be the preferred ingredient. The oath taken by the wardens of the Montpellier tanners since the thirteenth century indicated that they would inspect the “herbs” used in the tanning process to guarantee their quality, which included sumac and redoul. Redoul was a tanning plant widely used in Southern France and Catalonia. A 1335 ordinance from the city of Valencia, in Spain, specified that the tanning pits should be filled with herba de raudor [redoul] properly crushed. In Montpellier, the wardens of the tannery who inspected the pits had to make sure no other “herb” was mixed in the tanning liquor, and that no rocks or sand were found in the pits.
Medium and smaller skins were tanned in wooden or clay tubs or tanks. Tanners immersed the skins in the tanning liquid and had to stir them regularly until they reached the expected hue and texture—which took a few weeks. For the most delicate leather that would be used to make expensive and refined items, small skins were sewed together to form a small bag in which the tanning mélange was poured. Bags were then immersed in the tanning liquor for two or three weeks. Ordinances from Perpignan, southern France, issued in 1407, allowed the tanning of hides in small bags, but bags had to be filled with redoul leaves. Here too, once satisfied with their work, tanners rinsed the skins, smoothed them over, and let them dry. If not going through the process of tanning, the most delicate skins were tawed. Tawing is done by using a tanning liquor of alum mixed with flour, eggs and other substances. It yields white, soft and more fragile leather often used to make gloves and luxury products.
Horrific Stenches and Refuse
Medieval tanners at work in an illustration from the Balthasar Behem Codex, c. 1505. Note the dog defecating on the left, possibly a reference to the use of dog dung in the leather-tanning process. Jagiellonian Library, Kraków.
Tanners often settled near watercourses, because tanning requires a lot of clean running water to rinse the hides and prepare the tanning liquors. Furthermore, having a stream nearby came in handy to dispose of the tannery by-products: urine, lime, dung and one-year-old oak bark, sumac or redoul liquor. Downstream, residents were assaulted by the horrific stenches emanating from the now-polluted waters.
In London, tanners had established their workshops near the River Fleet, close to the Fleet prison and to the houses of affluent and influential residents. In the fourteenth century, the Fleet was already polluted by the presence of latrines which drained directly into the water stream.
But the establishment of too many tanneries only made the issue greater. King Edward III launched an inquiry in 1355 to investigate the issues with the “infection of the air” and the “abominable stench” arising from the tanners’ activities. The investigation concluded that the tanneries’ waste, including the excrement they used, had been dumped in the ditch near the prison, thus contaminating the river. Because of these issues, tanners and other great polluters (such as skinners) were often kept outside of a city’s walls, and at a distance from residential neighbourhoods. The city of Bristol had since 1344 prohibited tanners and girdlers from working “within the walls, to wit in the highways where the majority of the people pass”.
But not all tanneries were established near rivers. In several towns and cities, such as in England and Italy, tanners instead relied on wells and public fountains. But whether using running water, wells or public fountains, tanners were everywhere criticised for the stenches and the reckless disposal of the refuse of their craft. Ordinances issued in Siena, Italy, before the plague, strove to tackle several of these issues. Tanners were prohibited from throwing hides and lime into the large canal of one of the city’s public fountains. They were forbidden to put skins in laundry basins and to soak or tan hides in the immediate vicinity of another public fountain. The goal of these ordinances was to keep the most polluting and smelly steps of the tannery process downstream from the public fountains.
Making leather in the Middle Ages was a dirty and smelly business, involving everything from animal dung and urine to rotting hides. Lucie Laumonier explores how medieval tanners practised their craft and why their workshops became a major source of pollution in medieval towns.
By Lucie Laumonier
Before the invention of plastic, leather was essential in a broad array of sectors. From clothing and accessories to animal harnesses and saddles, from the fabrication of tool parts, parchment, bags and pouches, to quivers and armour, the leather industry fulfilled an essential function in medieval societies. The industry itself was divided into two realms of competencies: the preparatory phase which corresponds to the transformation of hides into leather, and the manufacturing phase that corresponds to the transformation of leather into products (‘leather-working’).
The preparatory phase involved a large range of actors who belonged, in the later Middle Ages, to different guilds: skinners, leather curriers, tanners, tawyers and cordwainers. In large and populated cities, boundaries between guilds regarding their expertise were usually tightly enforced. In Chester, England, the tanners obtained an ordinance in 1362 prohibiting the cordwainers from meddling with their trade. But in smaller towns there could be a significant overlap between the workers’ activities. In what follows, I’ll walk you through the process of leather tanning and tawing, with an eye towards the environmental implications of the process. Be careful, it was a fairly gross and noxious industry!
Preparing the Hides
Leather is an animal product: it is made from the hides of bovines, ovines and caprines, as well as from wild animals, such as deer. Tanners acquired hides from butchers. In England, archaeologists have indeed found large quantities of cattle horns in tannery pits located in Tanner Street in Northampton, which show that tanners received cattle hides with the horns and hooves still attached. In Montpellier, southern France, archaeologists recovered caprine heads and feet in pits located in the tanning quarter: there too, tanners received the hides with body parts still attached. Tanners therefore had to first remove the horns and lower appendages from the hides.
Then, it was time to wash and soak the hides to clear out any blood and dung left there. A late medieval treatise discussing skin tanning and written in Bologna, Italy, recommended that the hides should soak for five days “until the flesh is well macerated,” but specified that tanners should change the water every day or two days for the bad smell coming out of it. The soaking of hides was an issue for neighbours and residents. Brewers of Colchester, England, complained c. 1425 to the town that the tanners were laying hides in the River Colne and polluting the water. In fifteenth-century Ipswich, five tanners were fined for having soaked hides in a common well, which contaminated the drinkable water.
The next step was to detach the hair and hair roots from the skin. To ease the scraping-off process, tanners used different techniques. First, they could pile up the hides in a warm atmosphere until the hair started to detach. But to hasten their work, tanners soaked or sprinkled the hides with urine, lime or ashes, depending on the techniques they preferred. The lime I refer to here is calcium hydroxide, an alkaline agent—not the fruit. An Italian author of a tanning guidebook said that certain hides should be kept soaking in lime for fifteen days, all the while lifting up the hide twice a day and letting it drip for two hours. But the statutes of the tanners of Venice, dated 1401, stipulated that hides should remain in the lime for one or two days, then removed, and then put back in the lime for one week.
Regardless of the preferred process, and once properly soaked, hides were rinsed and spread over wooden beams to be scraped with a knife on both sides. It was then time to treat the skins to remove the excess lime, extend the skins and make them flexible. Skins could be immersed in a warm infusion of bird guano or animal dung, or drenched in fermenting cereals, such as barley, in which stale beer or urine was added.
Let’s pause here for a minute. The preparatory steps of the tanning process were already noxious and highly polluting. Animal hair, blood and fat were washed downstream; hooves and horns were buried into cesspits; piles of guano and of dog dung were laying around in the leather-working district and mixed with the smell of urine and fermented cereals. These products had to be washed and replaced, while a great quantity of water was required to wash and soak hides! In thirteenth-century London, the Walbrook River that ran by the tanners’ quarter was so polluted that it had become obstructed by dung, “rotten matter” and other unsavoury refuse.
Tanning (and spillovers!)
The next phase of the tanning process depended on the thickness of the hides, which were cut to the desired size. For the thickest and strongest leather, used, for instance, for shoe soles, belts or harnesses, hides were placed in pits, that is, large tanks set in the ground. Hides were arranged in horizontal layers, with layers of tanning products in between. Tanners added water to the pits to immerse all the skins properly. These were called layaway pits. After a while, tanners moved the skins to other pits filled with tanning liquor and cold water. Skins typically remained in these pits for about a year. Once satisfied with their work, tanners rinsed the skins, smoothed them over, and let them dry. But spillovers were a frequent issue. In fifteenth-century Ipswich, two tanners were accused of having kept their “barkepits” too close to a public watercourse, with the tanning liquor contaminating the stream. Because of this ongoing issue, it was decided in 1466 that tanning pits would have to be licensed and inspected by the town’s authorities to make sure their contents were not polluting any water source.
What about the tanning liquor? Boiled oak bark was used in England and Northern Europe as the main tanning agent, for it was readily available. In Southern Europe, other plants, such as sumac, tended to be the preferred ingredient. The oath taken by the wardens of the Montpellier tanners since the thirteenth century indicated that they would inspect the “herbs” used in the tanning process to guarantee their quality, which included sumac and redoul. Redoul was a tanning plant widely used in Southern France and Catalonia. A 1335 ordinance from the city of Valencia, in Spain, specified that the tanning pits should be filled with herba de raudor [redoul] properly crushed. In Montpellier, the wardens of the tannery who inspected the pits had to make sure no other “herb” was mixed in the tanning liquor, and that no rocks or sand were found in the pits.
Medium and smaller skins were tanned in wooden or clay tubs or tanks. Tanners immersed the skins in the tanning liquid and had to stir them regularly until they reached the expected hue and texture—which took a few weeks. For the most delicate leather that would be used to make expensive and refined items, small skins were sewed together to form a small bag in which the tanning mélange was poured. Bags were then immersed in the tanning liquor for two or three weeks. Ordinances from Perpignan, southern France, issued in 1407, allowed the tanning of hides in small bags, but bags had to be filled with redoul leaves. Here too, once satisfied with their work, tanners rinsed the skins, smoothed them over, and let them dry. If not going through the process of tanning, the most delicate skins were tawed. Tawing is done by using a tanning liquor of alum mixed with flour, eggs and other substances. It yields white, soft and more fragile leather often used to make gloves and luxury products.
Horrific Stenches and Refuse
Tanners often settled near watercourses, because tanning requires a lot of clean running water to rinse the hides and prepare the tanning liquors. Furthermore, having a stream nearby came in handy to dispose of the tannery by-products: urine, lime, dung and one-year-old oak bark, sumac or redoul liquor. Downstream, residents were assaulted by the horrific stenches emanating from the now-polluted waters.
In London, tanners had established their workshops near the River Fleet, close to the Fleet prison and to the houses of affluent and influential residents. In the fourteenth century, the Fleet was already polluted by the presence of latrines which drained directly into the water stream.
But the establishment of too many tanneries only made the issue greater. King Edward III launched an inquiry in 1355 to investigate the issues with the “infection of the air” and the “abominable stench” arising from the tanners’ activities. The investigation concluded that the tanneries’ waste, including the excrement they used, had been dumped in the ditch near the prison, thus contaminating the river. Because of these issues, tanners and other great polluters (such as skinners) were often kept outside of a city’s walls, and at a distance from residential neighbourhoods. The city of Bristol had since 1344 prohibited tanners and girdlers from working “within the walls, to wit in the highways where the majority of the people pass”.
But not all tanneries were established near rivers. In several towns and cities, such as in England and Italy, tanners instead relied on wells and public fountains. But whether using running water, wells or public fountains, tanners were everywhere criticised for the stenches and the reckless disposal of the refuse of their craft. Ordinances issued in Siena, Italy, before the plague, strove to tackle several of these issues. Tanners were prohibited from throwing hides and lime into the large canal of one of the city’s public fountains. They were forbidden to put skins in laundry basins and to soak or tan hides in the immediate vicinity of another public fountain. The goal of these ordinances was to keep the most polluting and smelly steps of the tannery process downstream from the public fountains.
Lucie Laumonier is a medieval historian and professor at Concordia University, Montreal. Her newest book is Charity and Community in Montpellier, 13th–16th Centuries: The Multiplication of Loaves. You can follow Lucie on Instagram @lucie_in_academia
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Further Reading:
John Blair, Nigel Ramsay (eds.) English Medieval Industries: Craftsmen, Techniques, Products (Hambledon Press: 1991)
Ricardo Córdoba (ed.), Craft Treatises and Handbooks: The Dissemination of Technical Knowledge in the Middle Ages (Brepols: 2013)
Michael Kucher, ‘The Use of Water and its Regulation in Medieval Siena’, Journal of Urban History 31, no. 4 (2005): 504-536
Carole Rawcliffe, Urban Bodies: Communal Health in Late Medieval English Towns and Cities (Boydell & Brewer, 2013).
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