It was in Machynlleth that the Welsh rebel leader Owain Glyndwr set up his Welsh Parliament in 1404. It therefore has some entitlement to the claim to be the 'ancient capital of Wales'.
There is evidence of human settlement in the Machynlleth area dating as far back as the Early Bronze Age (ca. 2750 years ago) with evidence of copper mining activity within a mile of the town centre. It may be that the legend of 'Cantre'r Gwaelod', the magnificent city and fertile plains now lost beneath the waves near Aberdovey speaks of this period, or of settlers further back in the mists of time - possibly as far back as the end of the ice age when significant sea-level rises re-shaped the coast of Britain.
Later, the Romans built a small fort at Pennal, some four miles west of Machynlleth, and archaeological evidence suggests there was modest Roman settlement in the area around this fort.
One of the earliest written references to Machynlleth is the Royal Charter of 1291, granted by Edward I to Owen de la Pole the Lord of Powys. This Charter allowed Machynlleth to hold a market every Wednesday and two fairs a year, a tradition that continues to this day. It is clear that the market and fairs helped Machynlleth to thrive throughout the Medieval period and right through to the Victorian era with evidence to suggest that animals came for sale from across the length and breadth of Wales and as far afield as Hereford and Shropshire.
This historic town boasts a number of interesting buldings in addition to Owain Glyndwr's Parliament building. Royal House which stands on the main through road is a great example of a mediaeval house. The front portion is today the town's Tourist Information Centre, and the building also houses a local heritage centre and self catering accommodation. It is belived that a rogue by the name of Dafydd Gam was imprisoned at Royal House between 1404 and 1412 for attempting to assasinate Owain Glyndwr. Following his release, historic annales show that Dafydd went on to fight alongside Henry V at the Battle of Agincourt and, indeed, he is named amongst the dead in Shakespeare's Henry V.
Another tradition associated with Royal House is that Charles I stayed there in 1643 - and hence the name 'Royal House'.
On 29 November 1644, near Dyfi Bridge a battle took place between Oliver Cromwell's army under the command of Sir Thomas Myddleton of Chirk Castle and the Royalists. Many were killed and a number of houses in Machynlleth that were occupied by Royalists were burned down.
In the ninteenth century, the daughter of a prominent local landowner married Viscount Seaham, the second son of the third Marquess of Londonderry and they made their home in Plas Machynlleth. On the death of his father, Viscount Seaham became Earl Vane. The grand clock tower which stands in the centre of Machynllet on the site of the old Town Hall was erected by the townspeople to celebrate the coming of age of Charles Stewart Vane-Tempest, Viscount Castlereagh, the eldest son of Earl Vane and his wife. The foundation stone was laid on 15 July 1874. Another of their sons, Lord Herbert Vane-Tempest was the last member of the family to live at the Plas, that can still be seen on the southern approach into Machynlleth. He was killed in the Abermule train collision on the Cambrian Railways, and after his death, Plas Machynlleth was firstly used as a military facility during the Second World war then given to the townspeople.