The dates in the Life of S. Catoc can only be fixed conjecturally.
(Lives of the British Saints)

S. Cadoc born " circ. 497
Founds Llancarfan circ. 518
Goes to Ireland for three years circ. 523-526
Settles in Brecknock at Llanspyddid circ. 526
Death of Gwynllyw and return to Llancarfan circ. 527
Leaves for Scotland, consigning his abbey to Gildas circ. 528-529
Departs on pilgrimage to Rome and Jerusalem circ. 544
Council of Llanddewi Brefi circ. 545-546
Return of Cadoc to Britain after the Council before 547
Disputes with Maelgwn and Rhun ab Maelgwn before 547
The Yellow Plague, goes to Armorica before 547
Returns to Llancarfan circ. 551
Summoned to Ireland by King Ainmire circ. 564
Returns to Llancarfan circ. 565
Resigns Llancarfan and retires to Beneventum circ. 575
Killed by the Saxons circ. 577

The dates in the Life of Germanus, Bishop of Man
(Lives of the British Saints)

Born in Armorica c. 410
Went to Ireland to S. Patrick c. 440
Leaves Ireland and takes charge of Brioc, Illtyd and Patrick mac Sannan c. 450
Leaves Gaul to meet S. Patrick in Britain c. 462
Engaged in contest with Vortigern c. 462-4
returns to Ireland and appointed first Bishop of Man c. 466 Dies in Man c. 474

The dates in the Life of S. Illtyd can only be fixed conjecturally.
(Lives of the British Saints)

He was born about the year 450
He became a disciple of Germanus of Armorica about 460
Left him when Gremanus returned to Britain circa 462
Became a knight and married 472
Converted by S. Cadoc and founded Llantwit 476
Retired to the banks of the Ewenny, and Samson made abbot provisionally 521
Returned to Llantwit and Samson left 525
Died between the ages of 77 and 87 527-537

The dates in the Life of S. Paulus Aurelianus approximately.
(Lives of the British Saints)

Born in Penychen c. 479
Goes to S. Illtyd at Ynys Pyr c. 490
Deserts S. Illtyd, and founds a cell along with other boys c. 496
Ordained priest c. 504
Goes to Caerbanhed c. 506
Leaves and goes into the South-west of Britain c. 508
Crosses into Armorica c. 510
Consecrated Bishop c. 516
Visited by S. Brendan c. 526
Resigns his See and succeeded by Joevin 553
Death of Joevin and succession of Tigernomagle 554
Death of Tigernomagle, Paul resumes his office.
Defeat and death of Conmore and elevation of Judual 555
Foundation of Gerber c. 560
Death of S. Paul 573

The dates in the Life of S. Samson rests mainly on the supposition that he died at the age of 80.
(Lives of the British Saints)

Samson born circa 485
put as pupil to Illtyd c. 490
ordained priest c. 515
converts his father and becomes Abbot of Ynys Pyr c. 516
goes to Ireland c. 518
returns and retreats into a desert c. 520
is consecrated Bishop and made Abbot of Llantwit c. 522
quits Llantwit and crosses into Cornwall c. 525
receives news of the death of S. Illtyd c. 537
meets S. Petroo at Padstow c. 543
quits Cornwall and settles at Dol c. 544
S. Teilo flying from the Yellow Plague visits him 547
Samson goes to Paris for the first time c. 553
Defeat and death of Conmore 555
Second visit to Paris, attends Council 556 or 557
Dies c. 565

The dates in the Life of Teilio
(Lives of the British Saints)

born c. 500
in Amorica to escape the yellow plague 547-555 (or 548-556)
died 9 February c. 560 (Roman Martyrology 2004)

The dates in the Life of Padarn
(Lives of the British Saints)

Came from Amorica to Wales 516
Present at the council of Paris 557
Died 18 May (558?)

The dates of Gildas
(Gildas, on the Ruin and Conquest of Britain)

Birth 491 (Adventus Saxonum 447 + 44)
Wrote his book 545 (Battle of Badon 518 - 491 = 27 & 518 + 27 = 545)
Summoned to Ireland by Ainmire 565 Death 570

The dates of Armel (Arthmael = Arthur)
(Albert Le Grande's Lives of Saints of Brittany: La Vie de S. Armel)

Birth 482
Battle of Badon 518
(Les vie des_saints St Armel, Albert LeGrande: 552 is before defeat of Commore in 555
so assuming Le Grande mistake of a digit) Death of Arthur: 562

The dates in the Life of Malo
(Lives of the British Saints)

S. Malo born not earlier than 525
quits Wales on the outbreak of the Yellow Plague 547
returns to Wales, and is ordained priest c. 550
revisits Armorica and settles at Aaron c. 552
The Paschal Celebration before Conmore at Corseul, March 28 555
Defeat and death of Conmore, and elevation of Judual close of 555
S. Malo goes to Paris to have the grants of lands confirmed c. 556
goes to Llancarfan to obtain assistants c. 557
Judual transforms the monastery of Aleth into a See, and S. Malo consecrated in Wales c. 578
Visit to Luxeuil before 600
Death of Judual and usurpation of Haeloc c. 605
Arrival at Aleth of S. Tyssilio c. 610
Death of Haeloc, succeeded by a period of anarchy c. 614
S. Malo deserts Aleth and settles near Saintes 615
Revisits Aleth, and dies on his way back to Saintes Nov. 15 621

The dates in the Life of Mewen son of Geraint
(Lives of the British Saints)

Before the death of his father Geraint at Longborth guess 500
death June 21 617 appears to be too late so 600 as he was active with St Smason against Conmore

The dates in the Life of David
(Lives of the British Saints)

Birth c495-500
Abbot of Old Bush and Henllan 527
Attends council at Llanddewi Brefi 545
Makes foundations in Gower 542
In Brittany to escape the Yellow Plague 547-551
Returns to Wales at Menevia 551
Invited by Ainmire to Ireland 565
Attend synod at Lucus Victoriae 569
Death 589

The dates in the Life of Brioc
(Lives of the British Saints)

440. Brioc born in Ceredigion 440
Germanus the Armorican leaves Ireland to establish schools for the Irish missions, and is given Brioc to train 450
Germanus returns departs with his pupils to Paris 454
Germanus returns to Ireland, and is sent by S. Patrick to be Bishop of Man. At the same time Brioc receives Priest's Orders and returns home. 465
Brioc founds churches in Ceredigion, and for awhile assists his old master in the Western Isles. 470
Germanus dies. 474
Troubles in Ceredigion through the invasion of the sons of Cunedda and the expulsion of the Irish. 480
Brioc compelled to leave. Goes to Cornwall, and eventually crosses to the Pagus Achensis in Brittany. 520
Brioc returns to Wales, and on coming back to his monastery in Brittany finds his nephew Tudwal in possession and unwilling to receive him back. He goes on to the land of Rouvre. 526
Visits the court of Childebert and has the grants made by Rhigual con- tinued. Returns to Brittany and dies. 530

The dates in the Life of Dubricius
(Lives of the British Saints)

Dyfrig born at Madley about the year 450
He founds Henllan 470
Removes after seven years to Mochros 477
Ordains S. Samson bishop at Llantwit 530
Retires to Enlli and dies 546

The dates of Llandaff diocese (Life of Dubricius)
(Lives of the British Saints)

The outbreak of the Yellow Plague and flight of Teilo and abandonment of several of the Dubricius Churches 547
Return of Teilo 556
Some of the disciples of Dubricius remain with Teilo, who secures certain of the Dubricius sites.
Devastation of Erging by the Hwiccas after the battle of Deorham 577
Death of Teilo and election of Oudoceus to Llandaff 580
Oudoceus sets to work to reoccupy the desolate sites in Gower and Erging, and obtains the grant of Mochros
Oudoceus dies and Berthguin succeeds 620
Berthguin obtains a concession of the rest of the Dubricius sites in Erging and reoccupies them.
The estates of Llandaff are further increased by grants made by Morcant, grandson of Mouric, to Berthguin.
Morcant, King of Gwent and Glywysing, dies 665

The dates in the Life of King Consantine abused by Gildas becoming S. Constantine.
(Lives of the British Saints)

Born, son of Cador son of Geraint, in 510
At 30 King of Domnonia (Devon) abused by Gildas 540
At 79 converted by St. Petroc 589
Visited S. David's and went on to Rathin at monastery Mochuda 590
He left Rathin to see Columba, in the year of the death of this Saint, and was sent on to Kentigern 597
At age 88, slain in Kintyre 598