The Black Lives Matters movement has shone a spotlight onto many aspects of everyday life but also our industrial heritage. While Bristol and Oxford have made headlines for their colonial past, Ystradgynlais, in the Swansea Valley has an equally saddening link.

Ystradgynlais, meaning ‘vale of the river Cynlais’ is a small Town between Swansea and Brecon. The Town evolved around the Iron works at Ynyscedwyn. The Iron Works dates to 1729 but it was almost a century later where the works and Ystradgynlais as an identity truly evolved.

The population grew dramatically between 1821–41 as George Crane developed the Ynyscedwyn Ironworks. Crane was able to transform the works and Ystradgynlais thanks to financial backing from Joseph Marryat.

Without this financial backing, Ynyscedwyn Iron Works and Ystradgynlais as it is today would not have existed. We can reveal, thanks to the ULC in London (London’s Global University) that this money came directly from the slave trade.   

The abolition of the slave trade cost the UK Government around £20 billion in today’s money in compensation claims. By modern expectations, we would assume that this fee was shared out by the 800,000 slaves within the British empire at the time. In fact, it was to compensate the slave owners for their loss. The slaves received nothing.

From these claims, we can see which British citizens owned overseas slaves and their home residence.

Joseph Marryat

Living in Ystradgynlais, Joseph Marryat put in 20 claims for over 1,500 slaves which he owned. Being compensated tens of thousands of pounds in the process (over one million pound in today’s money). It was this money and the money which he had previously made from the renting and selling of slaves which allowed the Town to develop.

This is a story which is sadly true of many places. One which we should all learn in school alongside our local history. The Town is one with a very direct link to the slave trade although the whole valley shares an in-direct one; coal.

Swansea Valley

It is worth remembering that in the 17th century, the world had not mastered the art of currency, certainly not on a global scale. If a British merchant wished to trade with an Indian, Portuguese, or African counterpart then the swapping of goods was the transaction. Indian cotton for Yorkshire Coal for example or Irish Beef for Portuguese sugar or Welsh Copper for African slaves.

This was sadly too often true.

In 1717, Dr John Lane from Bristol founded a dedicated Copper smelting plant in Llangyfelach, Swansea. The copper was imported from Cornwall. Several tons of coal were burned in the smelting of each ton of copper ore and so logically it made sense to bring the copper to the coal rather than vice-versa.

Other Brisolians would follow into these parts, including the son of John Coster who had been backed by William Dockwra (regarded as the founder of British independent Slave Trade). They took over sites in the Melin, Neath and White Rock by the Liberty Stadium now.

Copperlopolis’ was born in Swansea

It transformed the entire region. Coal would be transported from further up the valley to smelt the copper via wagonways and tramways. Villages developed and became increasingly populated around the coalfields as demand for coal grew.  

There is a saddening link between Bristol and its links to the slave trade and the rise in the industrial Swansea Valley. Thomas Coster (son of John Coster) part-owned the Amoretta, a purpose built 85-ton ship to carry African slaves from the Bight of Biafra.   

The Bight of Biafra was a major route in the slave trade. It is estimated that 1.6 million slaves left Africa through here alone. Knowing what the slave owners wanted in currency was at the very heart of the trade. Coster, with other Bristolian businessmen would pay close attention and confidently added two more ships, the Squirrel and Mary to their slaving fleet.

The slave owners were increasingly demanding Copper.

By 1780, 3,000 tons of Welsh Copper was exported to Africa each year (nearly 20% of all global Copper produced). Three to four tons of coal was needed to smelt one ton of copper ore. So, each year, between 9,000 and 12,000 tons of coal was needed to smelt Welsh copper exported to Africa.

It is no coincidence that this was at the height of the British slave trade nor that Bristol slave traders founded Copper works in these parts. Coal dug out from these mountains was used to smelt Copper in the Lower Swansea Valley which would be shipped to Africa and exchanged for slaves.

One problem facing slave traders was molluscs which would attack the wooden ships in the warmer seas. The underneath would need fixing and this would leave traders stranded at port for weeks at a time. Copper sheeting was the solution to attach to the bottom of the ships. The Gnoll company in Neath was formed for this very reason. 

It was not just Copper which was used as currency. Welsh wool was in high demand and often used in transactions. It was also becoming the ‘traditional’ slaving clothing. Although most of the Welsh clothing came from Mid-Wales.  

Welsh Clothing

In 1767 a 9 year old slave in Virginia escaped. The search included the term ‘wearing a Welsh cotton jacket’ in the local newspaper. The cotton was, as you would expect, wool but the loose terminology of the wording ‘Welsh cotton’ shows the scale of export to the colonies. Most slaves would probably be totally unaware of Wales as a country but would all know Welsh clothing.

But it was our coal and copper which really transformed this region and it was the West Indies, not Africa which took the bulk of exported Copper. Here copper was not used to purchase slaves but for slaves to work. Huge copper vessels for distilling rum for example, using sugar planted and farmed by slaves.

Most of the copper smelted in the Swansea Valley has incredibly close links to the slave trade, but it also played a role in it ending.


In 1807 the slave trade was abolished in the UK. A little over a decade earlier, Cornish businessman Pascoe Grenfell went into partnership with Owen Williams smelting copper in the Middle and Upper Bank in the Swansea valley. As the copper ran out underneath Cornwall in the 1820s, Grenfell searched for more.

International tariffs had made oversea imports unfeasible but were lifted which allowed Grenfell to look abroad. Cobra mine in Cuba was rich in copper and the destination chosen. The Royal Copper Mines of Cobra was set up as a business based in London, mining and exporting copper from Cuba into Swansea.  

 In 1838, 900 worked on the Cuban mines. Over half were African slaves.

This was brought to the attention of the UK government which was globally anti-slavery at the time; they were rightfully embarrassed. Even more so because Grenfell had been a sitting Member of Parliament that had supported the abolition of the slave trade.  

Following this, the UK introduced a particularly important legislation. ‘More effectual Suppression of the Slave Trade’. From now on, it was illegal for any British national to have any involvement with the slave trade whether as part of the empire or on foreign soil.

As well as Joseph Marryat in Ystradgynlais, in Neath, there is further remains of the wealth which surrounded the slave trade. The Gnoll estate was Herbert Mackworths registered address as he put in his compensation claim for his slaves based in Trinidad. Herbert was an MP for over twenty years.          

These are simply the claimants with local registered addresses. Many of the ‘money people’ of these times lived outside of these parts. It is too easy to look at the slave trade as something which happened thousands of miles away. It impacted every part of this valley and the globe in some way or other.

Jack Swan
Author: Jack Swan

Swansea genius.

Jack Swan

Swansea genius.


  • July 21, 2020 at 7:45 pm

    Joseph Marryat was not living in Ystradgynlais when he was claiming for his slaves. He was the MP for Sandwich.And Ynysgedwyn Iron Works did not cause any population boom in Ystradgynlais between 1821 – 1841.It was the huge expansion in coal mining that caused the population increase.Who wrote this – a primary school pupil?

    • July 22, 2020 at 5:03 pm

      Joseph Marryat was living in Caedegar Road in Ystradgynlais when he put in his compensation claims for the slaves which he owned. This is recorded in the official documents. You can read more about this and him here:- https://www.ucl.ac.uk/lbs/person/view/11416

      In 1801 there were 196 houses in Ystradgynlais. This increased tremendously alongside the expansion of the Iron Works. Coal did indeed play a role in Ystradgynlais and its development and the article explains how the slave trade also played a major role in the demand for coal in the entire Swansea Valley.

      This is not something people wish to easily accept but Ystradgynlais was founded, as it is today off the back of the slave trade.

      • September 2, 2021 at 2:57 am

        I would dearly like to know where I could find documentation of those 196 homes. I know my family goes back to this area (between Ystradgynlais & Abercraf) early on but looking at all the families at once might help. I would so appreciate it.
        I’ve not heard this either, it’s odd as I would have recognized the name Marryat had I come across it, there’s certainly an anglicized version of it!

  • July 22, 2020 at 12:16 am

    Excellent piece of research. This story must be told.

  • July 23, 2020 at 1:34 am

    What expansion of the Iron Works? While Cyfarthfa,Dowlais etc were booming,Ynysgedwyn Iron Works was still using charcoal in the furnaces.In 1836 Crane and Thomas found a way of using anthracite in the furnaces.As for Caedegar Street,have you seen it? There is no way a wealthy iron master lived there in a terrace house amongst miners.It may have been the address of some functionary for him.He regularly voted in Parliament during his time as MP for Sandwich in the 20s and 30s.Maybe he had a flying carpet. In 1837 Ynysgedwyn had three blast furnaces,none fired by anthracite.Marryatt invested in Ynysgedwyn in 1837,after the discovery of the hot blast method.How could he be involved in any population increase before 1837? His compensation claims were made before 1837,before he took an interest in Ynysgedwyn.He was certainly not living in a little terrace house amongst miners in Caedegar Road whilst representing Sandwich (Kent)and attending Parliament.The boom in the Iron industry occurred after 1840,with Ynysgedwyn adding three new furnaces by 1846 and the new Ystalyfera Iron Works building 11 blast furnaces.There was no boom in the iron industry in Ystradgynlais before 1840.And the biggest increase in iron production was from Ystalyfera.Ystalyfera had 1 blast furnace in 1938 and 11 by 1948.Do you have any facts to support this nonsense?

    • July 23, 2020 at 11:03 am

      I think you are in denial John. It is there in black and white on the link. I have no idea whether the street is the same now as it was 200 years ago but that was his address when he claimed for the slaves. And it is well known that Marryat had strong links to the Town and the Iron Works. Shocking bit of history and rightfully been made public. It is time that we all accepted the real truth of history and not pick and choose the bits that we want to, which is what you seem to be doing.

  • July 23, 2020 at 11:30 am

    The article claims that Marryatt was partly responsible for the population increase in Ystradgynlais between 1821 and 1841.Marryatt did not invest in Ynysgedwyn until 1837.Please explain to me how Marryatt was involved in Ystradgynlais from 1821.Ynysgedwyn Iron Works did not increase much in capacity until after 1840,when new furnaces using the hot blast method were built.So,how was Marryatt and his money involved in the population increase between 1821 and 1841? What is this ‘shocking bit of history’?

  • July 23, 2020 at 11:55 am

    I have looked at the addresses on the claims,and two addresses are given,one in Ystradgynlais and the other in Westminster.Owning a house in Ystradgynlais does not mean he actually lived there.He was returned as an MP for Sandwich in 1834,and was active in Parliament.Are we to believe that he lived in Ystradgynlais and travelled daily to Parliament in Westminster (the trains did not arrive in Ystradgynlais until the 1860s) rather than living in his other house in Richmond Terrace, Westminster,just down the road from Parliament? Please enlighten my ignorance.

    • July 23, 2020 at 9:45 pm

      Apparently he lived in what is now Maesydderwen school for 20 years. Possibly off and on, I don’t know. However pupils in the school have been learning about him. I only learnt about this today but It sparked my interest and made me want to read more.

  • July 23, 2020 at 1:17 pm

    The final bit of this poorly researched (was it researched) article is correct.Ystradgynlais was a ‘registered address’.To suggest that Marryatt lived in Ystradgynlais while he was an MP for Sandwich is naive and rather silly.

    “As well as Joseph Marryat in Ystradgynlais, in Neath, there is further remains of the wealth which surrounded the slave trade. The Gnoll estate was Herbert Mackworths registered address as he put in his compensation claim for his slaves based in Trinidad. Herbert was an MP for over twenty years.

    These are simply the claimants with local registered addresses. Many of the ‘money people’ of these times lived outside of these parts.”

  • July 23, 2020 at 2:12 pm

    John, I feel like you are using smoke and mirrors to try and avoid the basic facts.

    Joseph Marryat earned immense amounts of money from the slave trade.

    Joseph Marryat used this wealth to invest in Ynysgedwyn Iron Works.

    The Iron Works was a MAJOR part of the development in Ystradgynlais.

    Whether he spent 2 nights a year or 200 nights a year in Ystradgynlais is completely irrelevant to what this article is highlighting.

    You seem to be deliberately focussing on a part of the article which doesn’t taint the history of the Town.

    Do you accept that Joseph Marryat earned much of his wealth from the Slave trade? Do you accept that he invested in the Iron Works? Do you accept that the Iron Works is a part of Ystradgynlais’ heritage?

    This is all blatantly clear. It saddens me that you can read this and refuse to see the real issues here.

    • September 2, 2021 at 3:05 am

      For me it taints Marryat, but not the town. As far as I can tell while it gave very low income people work, subsistence level living doesn’t seem a massive takeaway for most of the people, probably less so early on. Do I feel bad about slavery? Of course. Do I feel like Ystradgynlais is somehow ‘responsible’? No, and my ancestors left due to the level of living they could make here. I can consider where the Marriot wealth *might* have originated (I’ve no idea if it’s the same family), but do I tie it to my family? Not by any of my family stories of poverty.

  • July 23, 2020 at 3:06 pm

    Don’t try to move the goalposts.This article claims that the increase in population in Ystradgynlais between 1821 and 1841 was due to the expansion of the Ynysgedwyn Iron Works as a result of Joseph Marryat’s investment.It then claims that Ystradynlais was “transformed” as a result of Marryat’s money.There are no facts to support this.Of course the Ynysgedwyn Iron Works is part of Ystradgynlais’ heritage.That is irrelevant in this debate.Nobody is denying how Marryat made his money.The question is did Marryat’s money cause an increase in the population of Ystradgynlais between 1821 and 1841,as the article claims? Please give me some FACTS to support these claims.Between 1821 and 1841 how many more people were employed in the Iron Works???? How many more people were employed in the mining industry in Ystradgynlais? What caused the increase in the population,coal or iron? Justify your claims. Any fool can make accusations,but can these accusations be supported with facts? You say I am avoiding the basic facts. So what are the basic facts that you say I am avoiding? I am always willing to learn something new,as long as it is correct.I look forward to a brief history lesson. But please,lets have some FACTS about the population increase between 1821 and 1841.

  • July 23, 2020 at 7:03 pm

    A question to those who want this tale ‘to be told’.What would be the title of the tale? ‘A Fairy Tale’ perhaps?

  • July 23, 2020 at 9:14 pm

    I don’t think it was a fairy tale for the African men, women and children involved in the slave trade. I fear there are some people who for whatever reason wish to hide away from the atrocities which occurred. Thankfully, these people are becoming the minority. Even if they often shout very loudly.

  • July 24, 2020 at 9:38 am

    No one is arguing about the slave trade.You made the statement that Ystradgynlais is a town built by slaves,that Marryat’s money transformed Ystradgynlais,that the town evolved around the Iron Works.Let’s see some evidence of this.You have completely ignored the impact of the coal mines and built a completely false picture of the supposed influence of the Iron Works.So let’s hear it. Can you support your claims that Marryat’s money was responsible for the population growth in Ystradgynlais between 1821 and 1841? Or is just hot air and propaganda? A feeble attempt to jump on the BLM bandwagon?
    I’ll give you some figures to start you off.The Swansea canal carried coal (and other cargoes) to Swansea for export.
    1804 – 58,235 tons of coal.
    1816 – 159,633 tons of coal
    1825 – 208,433 tons of coal
    1839 – 386,058 tons of coal.
    Now lets have you justify your claim that it was Marryat’s money that ‘transformed’ Ystradgynlais. That Ystradgynlais is a ‘town built by slaves’.If you can’t back up your claims,I expect an apology for the slander to the village.

    • July 24, 2020 at 10:16 am

      I feel like you are going to believe what you want to believe regardless. If you wish to believe that the Iron Works played no part in Ystradgynlais and its expansion then you fire away. Nobody is disputing the impact coal had on the entire valley and this is mentioned continually throughout the article. What is also mentioned is the role the slave trade had with the demand for coal in this valley and that the infrastructure such as the Swansea Canal would have been part-funded with money directly or indirectly linked to the slave trade.

      The entire valley, Wales, UK and the world are all linked to the slave trade in some way. Ystradgynlais has a close and clear link. This is not a slur on those who live there today or those who worked in the Iron works 180 years ago. It is something which people need to know, accept and add to our understanding of our local history

  • July 24, 2020 at 12:17 pm

    You are running away and moving the goalposts.Let me remind you of what you wrote in the article.”The town evolved around the Iron Works at Ynysgedwyn”. ” Crane was able to transform the works and Ystradgynlais thanks to financial backing from Joseph Marryat.” “Without this financial backing Ynysgedwyn Iron Works and Ystradgynlais as it is today would not have existed.” “The population grew dramatically between 1821 and 1841 as George Crane developed the Iron Works”.There is no mention of the fact -the fact- that the Iron Works was the junior partner of the coal industry.If George Crane – not Joseph Marryat – had not rescued Ynysgedwyn Iron Works it would have made little difference to the village.Ystradgynlais was built by coal miners,not iron workers or slave money. And as for the dates 1821 to 1841,Marryat did not invest in the Iron Works until 1837.The Iron Works was bankrupt in 1823 and had to be rescued by George Crane.You are jumping on the BLM bandwagon and trying to rewrite history,sweeping the coal industry under the carpet and trying to create an imaginary history of Ynysgedwyn Iron Works dominating Ystradgynlais.Your headline is actually correct “Ystradgynlais-town built by slaves”. You deliberately forgot to say they were white slaves.White men,women and children who laboured and died underground.Some of my ancestors – white men – died in the mines in Ystradgynlais,and your attempt to write them out of the village’s history is deeply offensive.

  • July 24, 2020 at 3:41 pm

    One important fact that is being omitted here is that the Anglo-British colonial regime that exploited the slave trade also exploited their first conquest, the colony of Wales. This otherwise excellently researched article completely overlooks the fact that the Welsh nation and people were themselves being exploited of the huge wealth of coal, iron, copper, slate and much more by the agents of England’s Empire. The native Cymry laboured and suffered extreme hardship, living in unfit housing and low wages so that English aristocratic investors could harvest the profit from the mineral wealth of Wales. Wales was a conquered nation, ruled from Westminster, with no control over its destiny. Its a travesty to point at the Welsh people and communities and accuse them of being the authors of slavery!

    • July 25, 2020 at 3:14 pm

      Agree Geoff. An issue with our history is that most of our Towns and villages are built around industry which required financial power to begin. This almost always came from England. Their wealth allowed them to dictate terms of employment etc… and in most cases they are seen as heroes today. It isnt to say that all arent. But it is sad that our local history is generally always about these rich, white and generally English men who generously gave us our area. The reality is that in most cases they exploited cheap labour and earned far, far more money from the back of them.

    • July 25, 2020 at 3:59 pm

      For Geoff Ifans : I’m interested in your points and would like to discuss on email – I managed the ‘From Sheep to Sugar‘ Project last year http://www.welshplains.cymru. You can link with me through there.

  • July 25, 2020 at 6:23 am

    Excellent thread highlighting the power or interpretations. You’re all right of course, to varying degrees.

  • July 25, 2020 at 10:53 am

    The article may raise excellent points and pose questions but, one common theme throughout this story, many stories, our history stands out. Regardless of colour, nationality etc. the theme is rich people exploiting poor people.
    Look around you and ask if it still happens today? What, if anything have we learned?

    • July 25, 2020 at 1:19 pm

      I think this is a very, very important point.

      The sad reality is that most rich people today are the descendants of the rich people from 200 years ago. The poor are the family of the poor from yesterday.

      I’ve researched my family tree and generally find people who were servants by 13 years old. I imagine Boris Johnsons family tree looks quite different.

  • July 26, 2020 at 7:17 am

    These links to slavery to Wales are very tenuous if not ridiculous! I think everyone mentioned in this poorly written article has nothing to do with Wales other than to exploit its natural recourses!

  • July 30, 2020 at 8:53 am

    A really top class article and very important for all of us living in the area to know
    See also my pamphlet Wales and Slavery published in 2007 by the Wales Office when I was Secretary of State

  • August 27, 2020 at 2:38 pm

    John is correct in saying that Marryat did not actually live in Cadegar Road. How do I know? My father talked about that family living in Maesydderwen – my Grandpa Foundry, who bought the Ironworks off the Cranes, knew them and was asked if he would look after the daughters for a while when the parents were away (one reason why Daddy, the youngest,, mainly spoke English as the family had to while the girls stayed with them.).
    While remembering and deeply regretting the inhumane treatment of the poor slaves, I cannot but despair of the. focus of flagellation on British involvement while ignoring the Arab traders and the Africans themselves in the trade.
    What is more, there is CURRENTLY a massive ongoing slave trade within Europe and elsewhere. Instead of indulging in the mistakes of the past, how about lessons learned being an impetus to focus on what is going on now?
    It is so easy to become engrossed in academic research, time is for action in the present.

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