On the day that the Guardian launched its powerful Cotton Capital project, the city of the paper’s birth was hosting a visit from the US ambassador that, intentionally and unintentionally, exposed Manchester’s complicated relationship with slavery. It began with a lunch meeting in a former bank in the city’s old financial district, which was built with cotton capital and, uncomfortably, has a depiction of slavery on a stained-glass window. It then proceeded to the newly restored Lincoln Square, where the ambassador, Jane Hartley, was shown the US president’s words of praise for the working people of Manchester, taken from his famous letter to the city, for their principled stance against slave-picked cotton. Abraham Lincoln wrote to Manchester cotton workers in response to a statement they sent to him in 1862, passed by a mass gathering. It is an extraordinarily powerful text that remains highly relevant in today’s divided times. “As citizens of Manchester, assembled at the Free Trade Hall, we beg to express our fraternal sentiments towards you and your country,” it says. “We honour your free states as a singularly happy abode for the working millions. One thing alone has, in the past, lessened our sympathy with your country and our confidence in it – we mean, the ascendancy of politicians who not merely maintained negro slavery, but desired to extend and root it more firmly. Since we have discerned, however, that the victory of the Free North in the war … will strike off the fetters of the slave, you have attracted our warm and earnest sympathy. “We joyfully honour you for exemplifying your belief in the words of your great founders: all men are created free and equal. You have enforced the laws against the slave trade. You have nobly decided to receive ambassadors from the negro republics of Haiti and Liberia, thus forever renouncing that unworthy prejudice which refuses the rights of humanity to men and women, on account of their colour.” One-hundred-and-sixty-one years ago, humble cotton workers from Manchester sent a clear message to the rest of the world: black lives matter. It is an uplifting story that forms part of our city’s long history of fighting the good fight for equality – a line that can be traced back 200 years through the campaign for LGBT rights to the suffragettes and Peterloo. Manchester’s radical tradition inspires me every day in my role as mayor and I see it as my responsibility to continue it. And yet I can’t rewrite history, nor should I sanitise it. Back in the 1860s, I can’t pretend that other voices in Manchester were not clouding the clarity of the cotton workers’ message – not least its most prominent newspaper. The Manchester Guardian opined that it was an “evil day when he [Lincoln] was chosen president of the United States”. The paper’s fierce anti-Lincoln stance was not, ostensibly, due to any support for slavery but more for the southern states’ right to self-determination. However, after the Guardian’s own research into its founders, it’s hard not to think that their business links may have influenced their editorial position. It is clear that this ambivalence about cotton wealth, and the slavery that produced it, went beyond the paper to the wider city. In his piece The struggle for a black history of Manchester, Lanre Bakare is right that more needs to be done to tell the story of how slavery shaped the city as well as spotlight more recent black Mancunian history, such as the fight of the boxer Len Johnson against the colour bar. I like to think that the cotton workers would have approved of the Cotton Capital project, although they might have been a little surprised at how long it has taken to come about. It is finally addressing this ambivalence head on. What makes it stand out, in our gesture-rich social media age, is the fact that it meets the suffragettes’ test of “deeds not words”. The decision of the Scott Trust to commit more than £10m to a restorative programme, including raising awareness of transatlantic slavery and its legacies in Manchester and beyond, is something we want to be part of. The programme could also support work that Greater Manchester set in train in the summer of 2020 after, like the Guardian, we went through our own process of reflection prompted by Black Lives Matter. In the middle of a pandemic that was inflicting great harm on minority communities due to insecure work and poor housing, we realised we needed to do more to turn our words of outrage into real deeds. We could see they sounded hollow to people still experiencing severe discrimination. So we established a new race equality panel and a leadership and mentoring programme with Operation Black Vote. We have initiated a review of the use of joint enterprise, which is widely felt to have unfairly sent too many young black men to jail. More positively, we decided, with our black communities, to make the launch of Black History Month an annual high-profile event at Manchester Cathedral. And yet when a two-year-old boy dies from mould in a poorly maintained home in Rochdale, and the housing ombudsman warns that the “othering” of residents by social landlords is “highly unlikely” to be an isolated incident, we get a stark reminder of just how much there is still to do. “Justice demands for the black, no less than for the white, the protection of law,” wrote Manchester’s cotton workers to Lincoln. Sadly, their words are as relevant in 2023 as they were in 1862. But we must live in hope that the next 160 years will bring more human progress than the last. Andy Burnham is the mayor of Greater Manchester. He served as the Labour MP for Leigh from 2001 until 2017