Pwyll, Prince of Dyfed

Pwyll Pendefig Dyfed (Pwyll, Prince of Dyfed) is the protagonist of the First Branch of the Four Branches of the Mabinogi, the 12th-century collection of Welsh mythological tales preserved in the Red Book of Hergest. His story begins in Glyn Cuch forest, where while hunting Pwyll drives off the hounds of Arawn, King of Annwn (the Welsh Otherworld), from a stag they had killed. As recompense for the insult, the two men agree to exchange bodies and kingdoms for a year and a day: Pwyll rules Annwn in Arawn's form, defeating Arawn's rival Hafgan in single combat, and earns the friendship of the Otherworld king. As a result of this feat, Pwyll is granted the title Pwyll Pen Annwfn — 'Pwyll, Head of Annwn' — a designation unique in Welsh mythology that links the Lord of human Dyfed directly to sovereignty over the Otherworld.

The second and most celebrated episode is anchored at Gorsedd Arberth — the mound of Arberth, near present-day Narberth in Pembrokeshire. The mound is described in the Mabinogi as a place where whoever sits upon it will either receive blows or witness a wonder. Pwyll sits there and witnesses a woman in gold silk on a white horse circling the mound: Rhiannon. She cannot be caught on horseback however fast the rider, until Pwyll calls out directly to her and she stops. Their courtship, the thwarted feast, and their eventual marriage form the heart of the First Branch.

While Rhiannon, Pryderi (their son), and Arawn each appear in the dataset as separate entries, Pwyll himself — the mortal lord who bridges human Dyfed and the Welsh Otherworld, and whose relationship with Annwn defines the mythological framework of the Mabinogi's First Branch — provides the narrative foundation that those entries presuppose. His primary location is the Gorsedd Arberth mound, near Narberth, placing him firmly in Pembrokeshire.