First Minister Rhodri Morgan has called for Wales to remember its contribution to the anti-slavery movement.
Poet Iolo Morganwg was an anti-slavery campaigner
He said the abolitionist cause was taken up by working class people and eminent figures like poet Iolo Morganwg and preacher John Elias.
Mr Morgan also highlighted the links between the industrial revolution in Wales and profits from the slave trade.
Events are being held across Wales on Sunday to mark the 200th anniversary of the abolition of slavery in Britain.
Mr Morgan warned against pointing the finger of blame for slavery at others.
"What we must guard against is smug self-satisfaction," he said.
"While the slave trade is mainly associated with the ports of Bristol, London and Liverpool, it must be remembered that the Welsh industrial revolution and profits from the slave trade went hand in hand."
Cyfarthfa Ironworks in Merthyr Tydfil, south Wales were founded by slave trader Anthony Bacon and historians believe its success was built on the profits of the slave trade.
The fortune gained from slave plantations in Jamaica by their owner Richard Pennant was crucial to his development of the slate industry and Penrhyn Castle in north Wales, it has also been claimed. He was also an anti-abolitionist MP.
"Welsh planters, agents and sea captains were directly involved, and ships used in the trade were built at Cardiff, Newport and Swansea," Mr Morgan added.
"Many ordinary working-class people were also indirectly connected - the seamen on the ships and the workers employed by the slave owners and industrialists."
But he also had praise for the people who took up the abolitionist cause in the last quarter of the 18th century, including preacher John Elias from Anglesey, who spoke out against slavery in Britain's biggest slave port, Liverpool.
And poet Iolo Morganwg, founder of the Gorsedd of Bards, who was an anti-slavery campaigner.
Mr Morgan also highlighted the work of Robert Everett from Flintshire, north Wales, who encouraged the Welsh in America to join the abolition campaign.
The Abolition of Slave Trade Act, which made it illegal to trade slaves throughout the British Empire and banned British ships from involvement in the trade, was passed by British Parliament on 25 March 1807.
Mr Morgan said the bicentenary was an important opportunity to reflect on the struggles of the past and to pay tribute to the courage and moral conviction of all those - black and white - who campaigned for its abolition.
"It is an opportunity to demand to know why slavery still exists in some parts of the world today," he said.
An event in St David's Hall, Cardiff entitled 'Valuing Freedom', will be one of a number of bicentenary events in Wales and the rest of the UK.
Slavery: The Welsh Connections is on BBC Radio Wales, 25 March and 1 April at 1330 GMT and both are repeated the following Monday at 1800 GMT.