The Lord Rhys’ Oath

The broken oaths of the Lord Rhys would have put him at risk of eternal damnation, according to the tenets of the 12th century.

Dr Robert Anthony

In 1191, Gerald of Wales, man of God, was outraged by the behaviour of his kinsman, the Lord Rhys:

After besieging [Nevern Castle] with a force of armed men, Rhys ap Gruffudd captured [it] from his own son-in law … William FitzMartin … in direct contravention of a whole series of oaths which he had sworn in person on the most precious of relics to the effect that William should be left in peace and security in his castle.

Gerald of Wales

In Gerald’s eyes, the offence was made worse, and another oath broken, by Rhys handing the Castle to his own son Gruffudd, ‘a cunning, artful man’ who, Rhys had sworn, would never be permitted to hold it.

Gerald makes it plain that these oaths were sworn by Rhys in person following the accession of Richard I in 1189—Henry II’s death having marked the end of an interlude of peace maintained between Rhys and the old king. The oath-taker was Rhys’s son-in-law, William FitzMartin, and it is likely that the oath was sworn at Nevern Castle.

What did swearing an oath mean?

In medieval times, in western Europe and elsewhere, religion was a fundamental part of everyday life to a degree almost unimaginable now. Heaven and hell were real and a person’s destination after death was determined by his or her conduct in life. This was, incidentally, also a system for the effective control by the Church and secular authority over the populace as a whole.

Swearing an oath was considered essential (as today) in circumstances where acceptance of the simple word of an individual was considered inappropriate. An oath was a three-way contract between the oath-giver, the oath-taker and, most importantly, a higher supernatural authority such as the Christian God.

This contract comprised three elements. First, a declaration by the oath-giver to the oath-taker to do, or not to do, something; second, the (tacit) presence of a higher authority, such as God, whose function was to witness and, if necessary, enforce the oath; third, (often implied) a ‘curse’ called down by the oath-giver on him- or herself should the oath be broken.

Just as in a court of law today (when the oath to tell the truth is made not to the court—whose function is to enforce the law of perjury—but to God) the giving of an oath was a very solemn matter. The oath-giver had to understand that the consequences of breaking it were serious—including, in medieval times, eternal damnation. To further impress this upon the oath-giver, the oath was administered in formal, precise (often archaic) language.

What would have been ‘the most precious of relics’?

Oaths were often fortified by the requirement for the oath-giver, when uttering the solemn, formal words, to touch the relics or, rather, the container (‘reliquary’) in which they were kept. A ‘relic’ was usually part of a deceased holy person’s body, or something that had belonged to him/her, preserved as an object of reverence. Today, someone giving an oath in court holds a bible.

Bayeux Tapestry: ‘Where Harold made the Oath [of allegiance] to Duke William’ [1064]. Note that Harold is laying his hands on two ‘reliquaries’ containing parts of the bodies of saints (‘the precious relics’)

Whose body parts?

St David (Dewi Sant), 6th century bishop and monk, was said to have performed miracles during his lifetime and, after his death, parts of his body were preserved in a reliquary housed in a shrine at St Davids where the faithful came to pray and ask favours. Rhys ap Tewdwr, grandfather of the Lord Rhys, swore an oath of loyalty on St David’s relics prior to his regaining the kingdom of Deheubarth at the battle of Mynydd Carn, 1081.

Were these the ‘precious relics’ on which the Lord Rhys made his oaths in 1189? This could not have been for, in 1089, the first shrine (and presumably the reliquary), was lost in a Viking raid and a ‘new’ shrine (now in the Cathedral presbytery) not constructed until 1275. Whilst the earlier shrine may have contained relics of St David, there is little reliable evidence that the new shrine ever did.

Broken oaths: consequences?

Gerald’s views are clear:

‘Vengeance is mine; I will repay, saith the Lord’… God ordained that soon afterwards the castle should be taken away from Gruffudd [Rhys’s son], who was the real author and contriver of this plot, and handed over to his brother Maelgwyn, the man he hated most in all the world. About two years later [1194] Rhys was planning to disinherit his own daughter [obviously Angharad, wife of William FitzMartin], his grandsons and two granddaughters. Instead he was made prisoner in a battle with his sons and locked up in this very same castle. God took vengeance on him in the most apposite way, for, as he well deserved, he was disgraced and discountenanced in the very place where he had perpetrated a base and shameful crime.

Video: Delun Gibby tells the story of William and Angharad, Rhys’ daughter

A happy family indeed (incidentally, Rhys fathered at least nine sons and eight daughters: the scope for family strife must have been almost limitless).

The Lord Rhys died suddenly of ‘pestilence’ on the 28 April 1197. Gerald has nothing to say on the destination of Rhys’s eternal soul but his body was laid to rest in St Davids Cathedral.

Dr Robert Anthony

December 2021


Christopher Caple, Nevern Castle – Castell Nanhyfer (Pembrokeshire Coast National Park, 2021)

Brett Devereaux, ‘Collections: Oaths! How do they Work’ A look at history and popular culture, (online, 2019)

A.K.R. Kiralfy, Potter’s Historical Introduction to English Law and its Institutions (London, 1962)

Dillwyn Miles, A Book on Nevern (Llandysul, 1998)

Dillwyn Miles (ed.), The Description of Pembrokeshire (George Owen of Henllys) (Llandysul, 1994)

Lewis Thorpe (ed. and trans.), Gerald of Wales: The Journey Through Wales and The Description of Wales (Harmondsworth, 1984)

R.F. Walker, ‘The Lordships of Pembrokeshire in the Thirteenth and Fourteenth Centuries’ in Pembrokeshire County History, Vol. II (Haverfordwest 2002)