To judge by the surviving visual evidence (stained glass, wall paintings, carvings and so on), David and Winifred (or Gwenfrewi) were the most popular saints in late medieval Wales. They were certainly the only Welsh saints to be formally canonised by Rome. Their shrines at St David’s and Holywell were among the most popular in medieval Wales.
The shrine at St David’s was largely destroyed by the Reformation bishop, William Barlow. Amazingly, Holywell survived the Reformation (possibly because of its connection with Henry VIII’s formidable grandmother Margaret Beaufort) and remained as a focus for pilgrimage throughout the seventeenth and eighteenth centuries. The Gunpowder Plot conspirators went there, travelling from Winifred’s other shrine at Shrewsbury, where her relics had been taken by the Benedictine monks. James II and Mary of Modena went there in 1687 to pray for a son. (Their prayers seem to have been answered - but the boy’s birth provoked a political crisis which led to James’s defeat and exile. The son became the ‘Old Pretender’, father of Bonnie Prince Charlie.)
The route between these two important shrines was not recorded until John Ogilby mapped it in 1675. The route is almost certainly medieval, though parts of it may have changed over time. From Holywell, it crosses the Clwydian Range south of Afonwen, then runs though Ruthin and Bala to Machynlleth and down the west coast.
The Cistercian Way follows or runs parallel with Ogilby from Llangwyfan to Holywell (on the way from Conwy to Basingwerk) and from Llangynhafal at least as far as Ruthin and possibly to Bettws Gwerful Goch (on the way from Basingwerk to Valle Crucis).