Llywelyn's coronet was for a while kept with the English crown jewels.

Llywelyn's coronet () is a lost treasure of Welsh history.

It is widely thought that Llywelyn's Coronet was destroyed alongside most of the original English crown jewels in 1649 by order of Oliver Cromwell ; however, an inventory taken by the new republican administration prior to the destruction of the crown jewels makes no mention of this coronet.

There is some confusion as to whether Llywelyn's coronet is what was referred to by some chroniclers as the " crown " or " jewel " of Arthur or if this was a separate more treasured artifact.

It is possible that this was either another pre-conquest dynastic coronet, similar to Llywelyn's, and potentially the crown of the Kings of Powys known as the Crown of Elisig.

The House of Stuart was descended from Walter fitz Alan, the first High Steward of Scotland, and he was believed to have been the grandson of Fleance and Gruffydd ap Llywelyn's daughter, Nesta verch Gruffydd.

During Llywelyn's boyhood, Gwynedd was ruled by two of his uncles, who split the kingdom between them, following the death of Llywelyn's grandfather, Owain Gwynedd, in 1170.

The Peace of Middle in 1234 marked the end of Llywelyn's military career, as the agreed truce of two years was extended year by year for the remainder of his reign.

Llywelyn's mother was Marared, occasionally anglicised to Margaret, daughter of Madog ap Maredudd, prince of Powys.

Elise ap Madog, lord of Penllyn, had refused to respond to Llywelyn's summons to arms and was stripped of almost all his lands by Llywelyn as punishment.

This was the low point of Llywelyn's reign, but he quickly recovered his position.

One was from his daughter Joan, Llywelyn's wife, the other from William I of Scotland, and both warned him in similar terms that if he invaded Wales his magnates would seize the opportunity to kill him or hand him over to his enemies.

Hubert had been given the lordship and castle of Montgomery by the king and was encroaching on Llywelyn's lands nearby.

Following his capture, William de Braose decided to ally himself to Llywelyn, and a marriage was arranged between his daughter Isabella and Llywelyn's heir, Dafydd ap Llywelyn.

During this visit he was found in Llywelyn's chamber together with Llywelyn's wife Joan.

The Brut y Tywysogion chronicler commented: " that year William de Breos the Younger, lord of Brycheiniog, was hanged by the lord Llywelyn in Gwynedd, after he had been caught in Llywelyn's chamber with the king of England's daughter, Llywelyn's wife ".

This truce was renewed year by year for the remainder of Llywelyn's reign.

This abbey was later moved to Maenan, becoming the Maenan Abbey, near Llanrwst, and Llywelyn's stone coffin can now be seen in Llanrwst parish church.

Little is known of Llywelyn's mistress, Tangwystl Goch, except that she was the daughter of Llywarch " Goch " of Rhos.

Gruffydd ap Llywelyn ( c. 1196 – 1244 ) was Llywelyn's eldest son and known to be the son of Tangwystl.

After Llywelyn's death on 11 December 1282, Gwenllian was captured by King Edward I and spent the rest of her life in a convent.

William was ransomed for the sum of £ 2, 000 and then furthermore made an alliance with Llywelyn, arranging to marry his daughter Isabella de Braose to Llywelyn's only legitimate son Dafydd ap Llywelyn.

However on a later visit to Llywelyn during Easter 1230 William de Braose was found in Llywelyn's private bedchamber with Llywelyn's wife, Joan, Lady of Wales.

:" In this year William de Breos the Younger, lord of Brycheiniog, was hanged by the Lord Llywelyn in Gwynedd, after he had been caught in Llywelyn's chamber with the king of England's daughter, Llywelyn's wife.

Llywelyn's daughter Gwenllian ferch Llywelyn was committed to a nunnery at Sempringham, while the sons of Dafydd were kept in Bristol Castle until their deaths.

Problems were exacerbated when Llywelyn's younger brother Dafydd and Gruffydd ap Gwenwynwyn of Powys, after failing in an assassination attempt against Llywelyn, defected to the English in 1274.

However, it was an attack on Brycheiniog by the Marcher Lords Humphrey de Bohun and Roger Mortimer in 1276 which led to the final breakdown of the peace between England and Wales after which Llywelyn's domain was reduced to just his lands in Gwynedd.

In June 1283 Dafydd ap Gruffudd, Llywelyn's brother, who assumed the title of Prince of Wales after Llywelyn's murder in December 1282, was captured at Bera Mountain above the present village.

The origin of its name, which translates as Dafydd's ( or David's ) cairn, like that of its neighbouring peak, Carnedd Llewelyn ( Llywelyn's cairn ), are named after Llywelyn ap Gruffudd, the last independent prince of Wales, and his younger brother, Dafydd ap Gruffudd.

Following Llywelyn's death in 1240, Gwynedd's power declined and many of its eastern lands were taken by Henry III of England in 1247.

However, Llywelyn's claims in Wales conflicted with Edward I of England, and war followed in 1277.

Llywelyn's relations with John remained good for the next ten years.

The Marshalls took advantage of Llywelyn's involvement here to land near St David's in April with an army raised in Ireland and recaptured Cardigan and Carmarthen without opposition.

Llywelyn's relations with John remained good for the next ten years.

Dafydd ap Gruffydd, Llywelyn's younger brother, attacked the English forces at Hawarden in 1282, setting off a widespread rebellion throughout Wales ; Edward responded with a further invasion of Gwynedd, during which Llywelyn was killed on the battlefield at Cilmeri.

Later he obtained recognition, at least in part, of this agreement from the King of England, who agreed that Llywelyn's heirs and successors would enjoy the title " Prince of Wales " but with certain limitations to his realm and other conditions, including homage to the King of England as vassal, and adherence to rules regarding a legitimate succession.

King John invaded Gwynedd and reached the banks of the Menai, and Llywelyn was forced to cede the Perfeddwlad, and recognize John as his heir if Llywelyn's marriage with Joan did not produce any legitimate successors.

Early in 1212 Llywelyn had regained the Perfeddwlad and burned the castle at Ystwyth. Llywelyn's revolt caused John to postpone his invasion of France, and Philip Augustus, the King of France, was so moved as to contact Prince Llywelyn I and proposed they ally against the English king King John ordered the execution by hanging of his Welsh hostages, the sons of many of Llywelyn's supporters Llywelyn I was the first prince to receive the fealty of other Welsh lords with the 1216 Council of Aberdyfi, thus becoming the de facto Prince of Wales and giving substance to the Aberffraw claims.

In 1219 he married Margaret Ferch Llywelyn, ( born about 1202 in Gwynedd ), daughter of the leader of Wales Llywelyn Fawr and his English wife Joan Plantagenet also known as Joan, Lady of Wales, and he received the Lordship of Gower as her dowry with Llywelyn's blessing.

Edmund sent a message to Llywelyn telling him he was coming to Llywelyn's aid and arranged to meet with him at Builth.

On Llywelyn's death it fell back into Norman hands, and in 1244 Earl Gilbert of Pembroke rebuilt it with town walls for added protection.

Another possibility is that Llywelyn's crown, which had been stolen in 1303 alongside the English Crown Jewels, had not been returned with the rest of them, and thus escaped destruction by Cromwell.