Math son of Mathonwy is the High King

High king

A high king is a king who holds a position of seniority over a group of other kings, without the title of Emperor; compare King of Kings.Rulers who have been termed "high king" include:...

 of the fictional realm of Prydain

Prydain

Prydain is the modern Welsh name for Britain.-Medieval:Prydain is the medieval Welsh term for the island of Britain . More specifically, Prydain may refer to the Brittonic parts of the island; that is, the parts south of Caledonia...

 in the Lloyd Alexander

Lloyd Alexander

Lloyd Chudley Alexander was a widely influential American author of more than forty books, mostly fantasy novels for children and adolescents, as well as several adult books...

 novel series The Chronicles of Prydain

The Chronicles of Prydain

The Chronicles of Prydain is a five-volume series of children's fantasy novels by author Lloyd Alexander...

. He rules above all lesser kings in Prydain. Math is patriarch of the Royal House of Don, comprising descendants of the Lady Don and her consort, Belin

Beli Mawr

Beli Mawr was an ancestor figure in medieval Welsh literature and genealogies. He is the father of Caswallawn, Arianrhod, Lludd Llaw Eraint, Llefelys, and Afallach. In certain medieval genealogies he is listed as the husband of Anna, cousin of the Virgin Mary...

, the Sun king. Math rules with a just hand, and through his leadership Arawn

Arawn

In Welsh mythology, Arawn was the king of the otherworld realm of Annwn, appearing prominently in the first branch, and alluded to in the fourth. In later tradition, the role of king of Annwn was largely attributed to the Welsh psychopomp, Gwyn ap Nudd...

, Death-Lord is at least partly held in check. He dwells in the stronghold Caer Dathyl

Caer Dathyl

Caer Dathyl was a Welsh fortress in Arfon in northern Gwynedd referred to in the Fourth Branch of the Mabinogi, the Tale of Math fab Mathonwy. Its precise location is currently unknown and has been the subject of speculation. In the tale, it is the seat of Math's court to which Gwydion ap Don...

, north of the Eagle Mountains. He appears fleetingly at the conclusion of The Book of Three and briefly in The High King

The High King

The High King is the last book in the Chronicles of Prydain fantasy series of books by Lloyd Alexander. It was awarded the Newbery Medal for excellence in American children's literature in 1969.-Plot overview:...

.

Overview

King Math is described as having a long white beard and his face is wrinkled with age. Upon his head, the Golden Crown

Crown (headgear)

A crown is the traditional symbolic form of headgear worn by a monarch or by a deity, for whom the crown traditionally represents power, legitimacy, immortality, righteousness, victory, triumph, resurrection, honour and glory of life after death. In art, the crown may be shown being offered to...

 of Don rests, but seems more like a cruel burden then a blessing.

In The High King, Math tells Taran

Taran (character)

Taran is a fictional character in The Chronicles of Prydain series, as well as in the film and game named after the second novel, The Black Cauldron.-Profile:...

 that he is deeply disturbed by the war that rages across his kingdom

Monarchy

A monarchy is a form of government in which the office of head of state is usually held until death or abdication and is often hereditary and includes a royal house. In some cases, the monarch is elected...

. He sadly laments that he wished that his kingdom remained in peace, rather than be engulfed by war and bloodshed. When King Pryderi

Pryderi

Pryderi fab Pwyll is a prominent figure in Welsh mythology, the son of Pwyll and Rhiannon, and king of Dyfed following his father's death. He is the only character to appear in all Four Branches of the Mabinogi, although the size of his role varies from tale to tale...

 arrives at Caer Dathyl and reveals that he has aligned himself with Arawn and vows to succeed in achieving peace, where the Sons of Don failed. King Math answers "Is there worse evil than that which goes in the mask of good?"

Pryderi's forces, along with Arawn's Cauldron-Born

Cauldron-Born

In Lloyd Alexander's series of fantasy books The Chronicles of Prydain, the Cauldron-Born are a race of deathless warriors in the service of Arawn, Death-Lord of Annuvin.- Origins :...

 warriors, launch an assault upon Caer Dathyl. When the deathless warriors batter down the gates, Math stands alone and defiant before them, armored in gold and holding a sword

Sword

A sword is a bladed weapon used primarily for cutting or thrusting. The precise definition of the term varies with the historical epoch or the geographical region under consideration...

. The Cauldron-Born warriors stride forward, knocking Math's sword aside and striking him down. Soon the lifeless warriors turn their battering ram

Battering ram

A battering ram is a siege engine originating in ancient times and designed to break open the masonry walls of fortifications or splinter their wooden gates...

s on the walls of Caer Dathyl, turning the once proud capital into a heap of rubble. The Chief Bard Taliesin

Taliesin

Taliesin was an early British poet of the post-Roman period whose work has possibly survived in a Middle Welsh manuscript, the Book of Taliesin...

 consecrates the ruined citadel as Math's barrow

Tumulus

A tumulus is a mound of earth and stones raised over a grave or graves. Tumuli are also known as barrows, burial mounds, Hügelgrab or kurgans, and can be found throughout much of the world. A tumulus composed largely or entirely of stones is usually referred to as a cairn...

.

Prince Gwydion

Gwydion

Gwydion fab Dôn is a magician, hero and trickster of Welsh mythology, appearing most prominently in the Fourth Branch of the Mabinogi, which focuses largely on his relationship with his young nephew, Lleu Llaw Gyffes...

 is the heir to Math's throne

Throne

A throne is the official chair or seat upon which a monarch is seated on state or ceremonial occasions. "Throne" in an abstract sense can also refer to the monarchy or the Crown itself, an instance of metonymy, and is also used in many expressions such as "the power behind the...

 and title, and briefly becomes the new High King after Math's death. It is never stated definitely whether Gwydion is in fact Math's son.

Like many aspects of the series, Math is based on a character from Welsh mythology

Welsh mythology

Welsh mythology, the remnants of the mythology of the pre-Christian Britons, has come down to us in much altered form in medieval Welsh manuscripts such as the Red Book of Hergest, the White Book of Rhydderch, the Book of Aneirin and the Book of Taliesin....

, Math fab Mathonwy, a legendary king.