The Welsh Triads
Peniarth MS 54 (formerly Hengwrt 536)

These triads are from the appendix of The Four Ancient Books of Wales, though I have altered the translation where it seems to better fit the original meaning.

TRIAD 1
Three Tribal Thrones of the Island of Prydain: Arthur as Chief Lord at Menevia [St David's], and David the Chief Bishop, and Maelgwn Gwynedd as Chief Elder. Arthur as Chief Lord in Celliwig in Cornwall, and Bishop Betwini as Chief Bishop, and Caradawg Vreichvras as Chief Elder; Arthur as Chief Lord in Penrionyd in the north, and Cyndeyrn Garthwys the cheif bishop, and Gurthmwl Guledic the Chief Elder.

TRIAD 2
Three Generous men of the Island of Prydain. Nudd the Generous, son of Senyllt; Mordaf the Generous, son of Serwan; Rhydderch the Generous, son of Tudwal Tudglyd.

TRIAD 3
Three Fair Princes of the Island of Prydain. Run son of Maelgwn; Owain son of Urien; Ruawn the Pefyr son of Deorath Wledig.

TRIAD 4
Three Naturalists of the Island of Prydain. Gwalchmai son of Gwyar; and Llachau son of Arthur; and Rhiwallawn Broom-Hair.

TRIAD 5
Three Pillars of Battle of the Island of Prydain. Dunawd son of Pabo Pillar of Prydain; and Gwallawg son of Lleenawg; and Cynfelyn Drwsgl (the Leprous?).

TRIAD 6
Three Bulls of Battle of the Island of Prydain. Cynfarch Cat Caduc son of Cynwyd Cynwytyon; and Gwenddolau son of Ceidiaw; and Urien son of Cynfarch.

TRIAD 7
Three Bull-Princes of the Island of Prydain. Elmwr son of Cadeir; and Cynhafal son of Argat; and Afaon son of Taliesin. The three of them were sons of bards.

TRIAD 8
Three Humble Princes of the Island of Prydain. Llywarch the Old son of Elidir Llydanwyn; and Manawydan son of Llyr Half-Speech; and Gwgon Gwron son of Peredur son of Eliffer of the Great Retinue.

TRIAD 9
Three Princes of Arthur's Court: Gobrwy son of Echel Mighty-Thigh; Cadreith son of Porthawrgaddu; and Fleudur Fflam.

TRIAD 10
Three Princes of Deira and Bernicia. Gall son of Disgyfdawd; and Ysgafnell son of Disgyfdawd; and Diffydell son of Disgyfdawd. The three of them were sons of bards.

TRIAD 11
Three Bloody-Speared Bards of the Island of Prydain. Tristfardd, bard of Urien; and Dygynnelw, bard of Owain; and Mainferdic, bard of Cadwallawn, son of Cadfan; and they were sons of Morgant.

TRIAD 12
Three Supreme Servants of the Island of Prydain. Caradawg son of Brān; and Cawrdaf son of Caradawg; and Owain son of Maxen Wledig.

TRIAD 13
Three Fleet Owners of the Island of Prydain. Geraint son of Erbin; and Gwenwynwyn son of Naf; and March son of Meirchiawn.

TRIAD 14
Three Strong-Crutched Ones of the Island of Prydain. Rineri son of Tangwn; and Tinwaed Faglaw; and Pryder son of Dolor of Deira and Bernicia.

TRIAD 15
Three Fettered Men of the Island of Prydain. Cadwaladr the Blessed; and Rhun son of Maelgwn; and Rhiwallawn Broom-Hair.

TRIAD 16
Three Knights of the Island of Prydain. Caradawg Vreichfras; and Menwaedd of Arllechwedd; and Llyr Lluydauc.

TRIAD 17
Three Hostile Ovates of the Island of Prydain. Greidiawl Galovyd, son of Enfael Adran; and Gweyr of great manliness; and Drystan son of Tallwch.

TRIAD 18
Three Red-spotted Ones of the Island of Prydain. Arthur; and Rhun son of Beli; and Morgant the Wealthy.

TRIAD 19
Three Battle-Leaders of the Island of Prydain. Drystan son of Tallwch; and Hueil son of Caw; and Cai son of Cenyr of the Fine Beard. And one was diademed above the three of them: that was Bedwyr son of Bedrawc.

TRIAD 20
Three Heroes of the Island of Prydain. Three sons of Haearnwedd the Wily: Gruddnei; and Henben; and Edenawg.

TRIAD 21
Three Arrogant Ones of the Island of Prydain. Sawyl High-Head; and Pasgen son of Urien; and Rhun son of Einiawn.

TRIAD 22
Three Obstructers of Slaughter of the Island of Prydain. Gilbert son of Cadgyffro; and Morfran son of Tegid; and Gwgawn Red-Sword.

TRIAD 23
Three Powerful Swineherds of the Islad of Prydain. Drystan son of Tallwch, who guarded the swine of March son of Meirchiawn, while the swineherd went to ask Essyllt to come to a meeting with him. And Arthur was seeking (to obtain) one pig from among them, either by deceit or by force, but he did not get it; And Pryderi son of Pwyll, Lord of Annwfn, who guarded the swine of Pendaran Dyfed in Glyn Cuch in Emlyn; And Coll son of Collfrewy, who guarded Henwen, (the old sow) of Dallwyr Dallben, who went about to bring forth to Penrhyn Awstin in Cornwall, and there she went into the sea. And at Aber Tarogi in Gwent Is Coed she came to land. And Coll son of Collfrewy with his hand on her bristles wherever she went, whether by sea or by land. And in the Wheat Field in Gwent she brought forth a grain of wheat and a bee; and therefore that place is the best for wheat and bees. And from there she went to Llonwen in Pembroke, and there she brought forth a grain of barley and a bee. From thence she made for the Hill of Cyferthwch in Eryri; there she brought forth a wolf-cub and a young eagle. And Coll son of Collfrewy gave the eagle to Brynach the Irishman of the North, and the wolf he gave to Menwaed of Arllechwedd; and these were the Wolf of Menwaed and the Eagle of Brennach. And from thence she went to the Black Stone in Llanfair in Arfon, and there she brought forth a kitten; and Coll son of Collfrewy threw that kitten into the Menai. And she was afterwards Palug's Cat. 

TRIAD 24
Three Enchanters of the Island of Prydain. Coll son of Collfrewy; and Menyw son of Teirgwaed; and Drych son of Kiwdar.

TRIAD 25
Three Great Enchantments of the Island of Prydain. The Enchantment of Math son of Mathonwy; and the Enchantment of Uthyr Pendragon ; and the Enchantment of Gwydelen the Dwarf.

TRIAD 26
Three Faithful Households of the Island of Prydain: The household of Cadwallawn son of Cadfan, who were with him seven years in Ireland; and in all that time they demanded no pay nor compensation from him; And the household of Gafran son of Aeddan, who went to sea for their lord; And the third, the household of Gwenddolau son of Ceidyaw at Arfderydd, who continued the battle for forty-six days after their lord was slain. The number of the households of each of those men was one-hundred-forty men.

TRIAD 27
Three Faithless Households of the Islands of Prydain. The household of Goronwy the Radiant of Penllyn, who refused to receive the poisoned spear from Lleu Skilful-Hand on behalf of their lord, at the Stone of Goronwy at the head of the Cynfal; and the household of Gwrgi and Peredur, who abandoned their lord at Caer Greu, when they had an appointment to fight the next day with Eda Great-Knee; and there they were both slain; And the household of Alan Fyrgan, who returned back by stealth from their lord, on the road at night with his servants at Camlan, and there he was slain.

TRIAD 28
Three Pass Retinues of the Island of Prydain. The retinue of Mynydawg of Eidyn; the retinue of Melyn son of Cynvelyn; and the retinue of Dryan son of Nudd.

TRIAD 29
Three Men who performed the Three Fortunate Assassinations of the Island of Prydain. Gall son of Dysgyfdawd who slew the Two Birds of Gwenddolau. And they had a yoke of gold on them. Two corpses of the Cymry they devoured for their dinner, and two for their supper; and Ysgafnell son of Dysgyfdawd, who slew Edelfled king of Lloegr; and Diffydell son of Dysgyfdawd who slew Gwrgi Garwlwyd. That Gwrgi used to make a corpse of one of the Cymry every day, and two on each Saturday so as not to slay on Sunday.

TRIAD 30
Three Unfortunate Assassinations of the Island of Prydain. The axe-blow of Eidyn son of Enygan on the head of Aneirin of Flowing Verse, Prince of Poets; and the axe-blow of Llawgad Trwm Bargod Eidyn on the head of Afaon son of Taliesin; and the axe-blow of Llovan Llawdifo on the head of Urien son of Cynfarch.

TRIAD 31
Three Unfortunate Hatchet-Blows of the Island of Prydain. The Blow of Eidyn on the Head of Aneirin; and the Blow on the Head of Golydan the Poet; and the Blow on the Head of Iago son of Beli.

TRIAD 32
Three Hosts that departed from this Island, and never returned. The first went with Elen of the Hosts and Cynan her brother, The second went with Yrp of the Hosts, who came here to ask for assistance in the time of Cadial son of Eryn. And all he asked of each Chief Fortress was twice as many men as would come with him to it; and to the first Fortress there came only himself and his servant. And it proved grievous to have given him that. Nevertheless that was the most complete levy that ever went from this Island, and no man of them ever came back. The place where those men remained was on two islands close to the Greek sea: those islands are Gals and Avena. The third host went with Caswallawn son of Beli, and Gwenwynwyn and Gwanar, sons of Lliaws son of Nwyfre, and Aranrot daughter of Beli their mother. And those men came from Arllechwedd. They went with Caswallawn their uncle across the sea in pursuit of the men of Caesar. The place where those men are is in Gascony. And the number that went in each of those Hosts was twenty-one thousand men. And those were the Three Silver Hosts: they were so called because the gold and silver of the Island went with them, as much as they could.

TRIAD 33
Three oppressions that came to this Island, and not one of them went back. One of them was the people of the Coraniaid, who came here in the time of Lludd son of Beli, and not one of them went back. The second Oppression was the Gwyddyl Ffichti, and not one of them went back. The third Oppression was the Saxons, and not one of them went back.

TRIAD 34
Three Concealments and Three Disclosures of the Island of Prydain. The Head of Bran the Blessed, son of Llyr, which was buried in the White Hill in London. And as long as the Head was there in that position, no Oppression would ever come to this Island; The second: the Bones of Gwerthefyr the Blessed, which were buried in the Chief Ports of this Island; The third: the Dragons which Lludd son of Beli buried in Dinas Emrys in Eryri.