Mention St Fagans, and for most people it will invoke memories of family days out at the Welsh history museum with its collection of historic buildings and displays.

But the place itself has a bloody history.

Just a short walk from St Teilo's church, Kennixton farmhouse, the Oakdale Workmen's Institute and other attractions at the open air museum is the site of probably the largest pitched battle ever to take place on Welsh soil.

The Battle of St Fagans saw some 11,000 men engaging in brutal hand-to-hand combat.

Hundreds of men were killed and legend has it that the river Ely ran red with their blood.

Many of those who fought and died had been on the same side just months earlier.

Today the site of the battle are peaceful, open fields with nothing to mark their significance - though artefacts such as musket balls and buttons are occasionally given up by the ground.

In 2016 the Battle of St Fagans was re-enacted at the site
In 2016 the Battle of St Fagans was re-enacted at the site

Background to the battle

The Battle of Fagans was the last big battle of the long-running English Civil War, the fight between parliamentarians, or "Roundheads", and forces loyal to the king - the "Cavaliers".

By 1647 most of the fighting in the war was finished, but disputes and infighting amongst the generals and landowners on the winning parliamentarian side rumbled on for many months.

Revolts began to break out around England and Wales, and in March the following year a number of prominent Welsh leaders switched sides from the parliamentarians to the royalists - even through they had just spent five years fighting against them.

Major general Rowland Laugharne, newly crowned commander-in-chief for Pembroke, Cardigan, Carmarthen and Glamorgan, was one of those who changed sides and now rallied to the king's casue.

He was joined by other senior figures including John Poyer, governor of Pembroke castle, Rice Powell, governor of Tenby castle, and the governor of Chepstow castle Nicholas Kemeys.

The uprising soon gathered support across Wales, bringing together those who had remained on the royalist side throughout the civil war with the newly converted to the cause.

In response, a detachment of troops from Oliver Cromwell's New Model Army was sent across the border to quash the rebels.

The scene was set for battle.

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The bloody battle

The two armies met on the morning of May 8 in fields west of Cardiff, not far from the village of St Fagans.

Some estimates put the size of the rebel army led by major general Laugharne as high as 8,000 men - a few hundred of them were cavalry but the bulk were unskilled volunteers known as "clubmen" who were armed with clubs and other simple weapons.

The two armies met at St Fagans
The two armies met at St Fagans

Opposing them was the parliamentary army lead by colonel Thomas Horton. It was a much smaller force - some 3,000 cavalry, infantry and dragoons - but was well-trained and disciplined. And they had reinforcements on the way led by Cromwell himself.

Just after 7am the battle began, with the rebels launching a surprise attack.

Accounts of the battle tell of a relatively short-lived but bloody affair - a type of combat we today might call "guerrilla warfare" with Laugharne's men using the ditches and hedges that criss-crossed the fields as best they could to help them pick off their more professional opponents.

The skirmishes ranged over a wide area, and pockets of troops fought each other at close quarters.

For two hours the sides fought with muskets, clubs, and bill-hooks - long poles with a hooked blade on the end - as well as on horseback.

But the superior skills and equipment at the New Model Army won the day - despite a last-ditch cavalry charge into their ranks led by Laugharne himself.

With defeat inevitable, Laugharne and his senior officers fled back west to Pembroke where they barricaded themselves in the town's castle.

Pembroke castle
Pembroke castle

Behind them they left hundreds of dead comrades - estimates vary from 300 to 700 - while another 3,000 men had been taken prisoner.

It was said the blood from the battlefield flowed into Nant Dowlais and then downstream into the Ely, turning the river red.

After the battle

The rebellious Laugharne was captured following an eight-week siege of Pembroke castle, and taken to London along with Poyer and Rice for courts-martial.

All were condemned to death but it was decided only one of them should be executed. However, the men refused to draw lots to see who should die and who should live, so the job of pulling a name out of the hat was given a child. 

Poyer was shot in front of a large crown in Covent Garden on April 21, 1649.

St Fagans was one of the last big battles in the bloody conflict between the roundheads and the cavaliers. In 1649 King Charles I executed, and England and Wales became a republic ruled by Oliver Cromwell.

One of those who signed the king's death warrant was the same colonel Horton who had led the parliamentarians at St Fagan's.

Laugharne remained a prisoner until the restoration of the monarchy in 1660. The following year he became MP for Pembroke and returned to London to sit in parliament.

Today it is history of different kind draws people to St Fagans - but next time you go to the museum why not pay the battlefield a visit.