Owain Gwynedd (circa 1100 to 1170), also known as Owain ap Gruffudd, was a Welsh leader and ruler of the Kingdom of Gwynedd, best known for his resistance against Henry II of England (reign 1154 to 1189). He is not to be confused with the later Owain ap Gruffydd, known as Owain Cyfeiliog.

Owain became tywysog (leader, ruler) of the Welsh kingdom of Gwynedd after his father's death in 1137, ruling until his own death in 1170. He is remembered for his political and military successes, his repulsion of Norman advances, and his unifying role in a fragmented Wales, having been described as "able to give them wise and enlightened guidance" (Lloyd, 487) and "worthy to guide his nation" (Barbier, 15). Owain led troops against King Henry II several times and sought diplomatic support from Louis VII of France (reign 1137 to 1180). In his final years, Owain was embroiled in a dispute with Thomas Becket, Archbishop of Canterbury, which led to his excommunication. Following his death from natural causes in 1170, Owain's domain fractured and was contested by his sons.

Owain's life is recorded in the Welsh chronicles the Brut y Tywysogion (The Chronicle of the Princes) and Annales Cambriae, and details of his military actions against Henry can be found in Anglo-Norman sources such as the Gesta Stephani, Chronicon ex chronicis, Gervase of Canterbury's historical works, Jocelin de Brakelond's chronicle, Roger de Hoveden's Annals, and William of Newburgh's The Church Historians of England. Some information on Owain's earlier years can be found in the biography of his father, the History of Gruffydd ap Cynan, the only surviving contemporary biography of a medieval Welsh prince.

Little is known of Owain's youth. The Brut y Tywysogion first mentions him in 1124, at which point he was likely already in his twenties. No record exists of his date or place of birth.

Owain was born to Angharad ferch Owain and Gruffudd ap Cynan, tywysog of Gwynedd. Through his father, Owain descended from Rhodri Mawr (Rhodri the Great), and through his mother from Hywel Dda (Hywel the Good). Owain's father, Gruffudd, was born in Dublin to the exiled Cynan ab Iago and spent two decades attempting to regain his ancestral lands in Gwynedd, finally succeeding in 1099 and holding Gwynedd until his death. It was shortly after this success in 1099 that Owain was born.

As Gruffudd aged and lost his eyesight, he delegated military leadership to his sons. It is in this role that Owain first appears in the contemporary record, leading a campaign into Meirionnydd in 1124 alongside his older brother, Cadwallon. Meirionnydd, a cantref (administrative region) in the south of Gwynedd, had been under the control of the kingdom of Powys, but this Powysian hold had been weakened by a succession dispute. This situation was effectively exploited by Owain and Cadwallon, who brought Meirionnydd under direct control of Gwynedd and returned north with a train of captives.

In 1132, Cadwallon was killed by his own cousins, Cadwgan ap Goronwy and Einion ab Owain, possibly during an attempted expansion into Powys. Owain was now Gruffudd's eldest heir. He continued to lead his father's forces, now alongside his younger brother, Cadwaladr. Their military talents would soon come in useful.

The death of Henry I of England in 1135 sparked a national revolt across Wales, and the opportunity to harry Norman settlers and regain lost land was seized. When the powerful Norman lord Richard fitz Gilbert was killed on his way to defend the land of Ceredigion, which had been granted to him by Henry I, Norman hold on Wales was further weakened, providing new opportunity for the Welsh to frustrate Norman control.

Owain and Cadwaladr wasted little time. In 1136, the pair marched south, leading an army out of Gwynedd and into Ceredigion, besieging a number of Norman-occupied castles and returning home victorious. The Brut y Tywysogion recorded their successes with a glowing eulogy, calling the pair "the splendour of all Britain and her defence and her strength and her freedom… defenders of the churches, guardians of the poor, slayers of their enemies and tamers of warriors… supremacy over all Wales…" (Jones, 51).

That same year, Owain achieved one of his greatest victories at the Battle of Crug Mawr. Returning to Ceredigion in the autumn of 1136, Owain and Cadwaladr were joined by the forces of Gruffydd ap Rhys, tywysog of the kingdom of Deheubarth, Hywel ap Maredudd, lord of Meisgyn in South Wales, and Madog ab Idnerth, another notable figure who hailed from a central part of the Welsh Marches. Near the hill of Crug Mawr, north of Cardigan, the combined Welsh force met their Norman opposition. The defending army was led by an alliance of leaders hoping to stem the Welsh uprising and reaffirm Norman control. The battle was a rout for the Normans, who were forced to retreat across the River Teifi. As the Welsh pursued, the bridge spanning the Teifi collapsed, sending many Normans to their death in the water. Welsh and Norman sources both report great Norman losses, with combatants trampled, burnt, slain, and seized. The Brut y Tywysogion claims 3,000 Normans had died by the time Owain and Cadwaladr, "having honourably won the victory" (Jones, 52), returned to Gwynedd.

When Gruffudd ap Cynan passed away in 1137, his realm was divided between Owain and Cadwaladr. Not only were Gruffudd's former lands contested regularly by his sons and grandsons following his death, but the sovereignty of North Wales was also threatened from the east by the Anglo-Normans.

In 1143, an opportunity arose for Owain to seize control of Gwynedd in its entirety. This year, Anarawd ap Gruffydd, tywysog of the kingdom of Deheubarth and ally of Owain, was slain by followers of Cadwaladr. Owain had promised to marry one of his daughters to Anarawd, and thus reacted fiercely to the news of the killing. Such a marriage would have brought the two kingdoms of Gywnedd and Deheubarth into a close and powerful alliance. However strongly the slight may have upset Owain, it also provided him with grounds to turn upon his brother and seize his lands. That year, Owain's son, Hywel ab Owain, attempted to capture Cadwaladr's holdings in Ceredigion, and later razed a castle belonging to Cadwaladr in Aberystwyth. Shortly after, Cadwaladr was expelled by Owain from the entirety of Gwynedd and fled to Ireland.

Cadwaladr never regained control of his lost lands from Owain, and their relationship remained mercurial for the rest of their lives. In 1144, a year after Anarawd's death, Cadwaladr returned from Ireland, having gathered a fleet, and landed at Abermenai in an attempt to reclaim part of Gwynedd. Conflict was avoided, and Owain permitted Cadwaladr to return to Wales, but the brothers' reconciliation would not bring lasting peace.

Owain continued to extend Gwynedd's power after the death of his father and despite dynastic struggles with his brother and nephews. In 1146, Owain's son Hywel ab Owain, alongside Tywysog of Deheubarth, Cadell ap Gruffydd, successfully besieged and captured the Norman-held castle of Carmarthen.

That same year, Owain's eldest son, Rhun, died, casting him into a lingering depression. The Brut y Tywysogion claims that even valuable treasures, performances from bards, and visits from his courtiers failed to lift his spirits. His low mood remained until later that year when he and his soldiers descended upon Mold Castle, a stronghold constructed by the Normans on Gwynedd's east. Owain's forces succeeded where others before had failed, dislodging the Normans and bringing the castle under Welsh control. Following this victory, Owain's grief apparently left him, and he returned to high spirits.

Family strife continued as, in 1147, conflict arose between Owain's sons, Hywel and Cynan, and their uncle Cadwaladr. In 1149, Owain constructed a castle in Iâl, Powys, whilst Cadwaladr constructed one of his own in Llanrhystud, Ceredigion. One year later, Owain imprisoned his own son, Cynan, likely in response to the latter's increasing power, while Hywel, Owain's second son, captured Cadfan, son of Cadwaladr, seizing control of his lands and castle.

Threats came from outside the family, too. In 1150, Owain squashed the uprising of Madog ap Maredudd, tywysog of Powys. His victory allowed him to check Madog ap Maredudd's power and continue extending influence into Powys.

It appears Owain also saw a threat to his rule in Cunedda, the son of his now deceased brother, Cadwallon. In 1152, Owain ordered Cunedda to be blinded and castrated. That very same year, Owain once again exiled Cadwaladr, driving him from Anglesey. When Cadwaladr next returned to Gwynedd, it would be in the service of King Henry II of England.

Owain did not achieve his power without making a few enemies. Chief among them was his brother, now joined by Madog ap Maredudd, the recently disenfranchised tywysog of Powys. The pair found an outlet for their frustrations in 1154, when Henry II ascended to the throne of England. Seeking to reassert royal control over the Marches and add Wales to his domain, Henry enlisted their aid. Henry likely promised Gwynedd to Cadwaladr and Powys to Madog as his vassals in return for their service.

Henry launched his first invasion of Gwynedd in 1157, and it would begin and end with the Battle of Coleshill, also known as the Battle of Coed Ewloe. Henry led a vast army overland into Tegeingel, a frontier cantref recently brought under Owain's control, and sent a supporting fleet toward Anglesey. Anticipating Henry's arrival, Owain entrenched his troops south of the River Dee, awaiting Henry's forces. Henry decided to flank the Welsh position, personally leading a detachment on a concealed march through the forest of Coleshill. However, Owain had anticipated such a manoeuvre and had sent his sons to lead their own band into the forest to await the king's arrival. The ensuing ambush was a rout for Henry. Caught off guard by the ambushing Welsh force and poorly prepared for the terrain, the royal force suffered great losses, including a number of notable Norman lords. Henry of Essex, the king's standard bearer, even dropped the royal standard and fled in the mistaken belief that the king had been slain. Henry II barely escaped, succeeding in struggling from the fray and retreating southeast and rallying his troops. Owain left his own entrenched position shortly after, moving westward. Henry II's army followed and, as they marched further into Wales, was harassed constantly by Owain's forces.

The naval contingent fared even worse. After disembarking and pillaging the island, the king's forces were met by the defenders of Anglesey and almost entirely slaughtered. Among the dead was Henry FitzRoy, illegitimate son of Henry I.

Defeated, Henry II sued for peace. Owain agreed to hand over several castles in the northwest to Norman control and to restore Cadwaladr to his lands. Yet he still retained control over Gwynedd, and the threat of Anglo-Norman invasion was quelled, for now.

In 1163, Owain attended the Council of Woodstock, where Henry compelled the rulers of Wales and Scotland to perform homage. Yet the submission of the Welsh leaders proved hollow. By 1165, the peace was no more, and Owain, united with Rhys ap Gruffudd, tywysog of Deheubarth, sought to regain territory lost to Henry. It is clear that they saw the agreement made at Woodstock as little more than a compelled and temporary truce, and that they neither viewed nor accepted Henry as their overlord. Whilst Rhys campaigned in Ceredigion, Owain sent his son Dafydd into Tegeingl, where he ravaged Anglo-Norman holdings and carried off captives. Fearing for the Norman-controlled castles, Henry returned to Wales, remaining briefly in Rhuddlan to strengthen his holdings. He then departed for England to prepare for his next thrust.

Henry returned in 1165, leading his army through Oswestry. His reappearance galvanised Welsh resistance, and Owain led a broad Welsh coalition that included Rhys ap Gruffudd of Deheubarth, Owain Cyfeiliog, and Iorwerth Goch ap Maredudd of Powys, and perhaps most surprisingly, his own brother, Cadwaladr, who had changed sides once again since the Battle of Coleshill. Once in Wales, Henry's men felled the surrounding forests to prevent the Welsh from using the cover to their strategic advantage. Whilst at work clearing the trees, the king's soldiers were met by a Welsh sortie, forcing Henry II to retreat into the Berwyn mountains, where he was beset by failing provisions and worsening weather. The king, cornered, furious, and unwilling to face his opponents, mutilated the Welsh hostages he had brought with him, who had likely been handed over at Woodstock. Among them were Owain's sons, Cadwallon and Cynwrig. Henry turned and retreated, determined to return the following year.

Henry's planned return to Wales never materialised. His failed invasions prompted policy reassessment in England and reinvigorated the desire for unity and independence in Wales. To secure his position, Owain turned to diplomatic means, making the unprecedented move of seeking an alliance with Louis VII of France. No earlier example is known of such international diplomacy made by a native Welsh ruler. In his letters to Louis, Owain referred to himself as Waliarum princeps (prince of Wales), marking the first recorded adoption of the title by a Welsh ruler.

Owain sent three letters to the Capetian court: one to Louis and one to his chancellor. In them, Owain recounts his military successes, rejects Henry's overlordship, offers his friendship to Louis, and requests the French king's aid, pledging to harm and harry Henry's interests should Louis wage war against England. The letters demonstrate the almost nationwide authority Owain held late in his reign.

If Louis replied, his responses are lost. Yet Owain evidently honoured his half of the proposed bargain. In 1166, Henry was forced to turn his attention toward France, spending the next four years on the continent. His absence was not squandered. By 1167, Owain, alongside Cadwaladr and Rhys, had successfully removed the final Norman strongholds in North Wales: Prestatyn and Rhuddlan. For the final three years of his life, Owain's control of North Wales was uncontested.

Owain did not spend his final years idly. Whilst he had strengthened Wales' temporal independence, ecclesiastical independence was harder to secure, and Owain spent his final years embroiled in a dispute with the Anglo-Norman church. Following the death of the bishop of Bangor in 1161, Owain refused to fill the see with a Norman appointee, defying the archbishop of Canterbury, Thomas Becket, and Pope Alexander III. Owain insisted his own candidate be consecrated by the Archbishop of Dublin, and maintained that Welsh obedience to Canterbury was a favour rather than a requirement.

Becket turned to the pope for support, and together the pair applied further pressure, denouncing Owain's marriage to his second wife, Cristin, and demanding the two separate on the grounds that the pair were cousins. Owain refused and was soon after excommunicated. This sentence, however, proved ineffective. The Welsh clergy stood by him, and Dafydd of Bangor, Becket's own appointee as administrator of the see, had defected to Owain's cause during the dispute. Thus, in his waning years, Owain achieved a final victory against Norman incursions, besting the Archbishop of Canterbury with his wit as he had the King of England with his sword.

Owain died in 1170 and was buried, despite his excommunication, in Bangor Cathedral. The Brut y Tywysogion memorialised him as "the bulwark of all Wales" and "unconquered from his youth" (Jones, 65). Poets Gwalchmai ap Meilyr and Cynddelw Brydydd Mawr both praised his military prowess and regality, whilst Gerald of Wales commended his wisdom and moderation, though condemned his consanguineous marriage.

Owain's contemporary reputation appears well-founded. He expanded and strengthened the kingdom inherited from his father, securing North Wales and projecting his authority southward until he could be considered the foremost leader of native Wales. He defied the military and ecclesiastical leaders of Anglo-Norman England, and variously fought alongside and against other native Welsh powers as needed. Driven by Welsh independence, he claimed for himself, and received from his peers, the titles of King of Wales and Prince of the Welsh. His rule foreshadowed the successes of his grandson, Llywelyn ab Iorwerth, who rose to the position of native Wales' dominant power almost 40 years after Owain's death.

In his life, Owain had mostly kept a lid on the simmering ambitions of his sons, but after his death, open conflict bubbled to the surface. Hywel, his eldest surviving son, was killed by his half-brothers Dafydd and Rhodri almost immediately after their father's demise, and the power struggle between Owain's descendants only continued from there. It was decades before one ascended above the rest: Owain's grandson Llywelyn ab Iorwerth, who would later be known as Llywelyn Fawr, Llywelyn the Great.