Now a group of walkers is re-tracing his steps.
They set off from Shrewsbury Abbey on 18 June, ending up at St Winefride's Well a week later.
The walk is part of a week of events to commemorate the historic royal visit and which, it is hoped, will boost the profile of the town.
"Holywell has an incredible, unique history," said Rob Owen, one of the organisers of the town's upcoming medieval festival.
"Castles are ten a penny in Wales,  but there's only one St Winefride's Well."
Mrs Owen is rightly proud of her town's famous landmark - St Winefride's Well has been a place of pilgrimage for more than 1,300 years and is the oldest continually venerated shrine of any British saint.
According to legend, Winefride was the daughter of a 7th Century nobleman, who shunned the amorous advances of a local prince named Caradog.
Furious at her rejection, Caradog beheaded her as she ran towards the safety of her uncle's church.
Her severed head rolled down the hill and a powerful spring burst up from the earth at the place it came to rest.
But all was not lost for Winefride - her uncle, St Beuno, placed her head back on her body and prayed and miraculously, she was restored to life.
Caradog, meanwhile, met a sticky end:  cursed by St Beuno, his body melted and was swallowed up by the earth.
Winefride became a nun and later, Abbess of Gwytherin in Conwy, where she died and was buried.
The healing waters of her well are said to bring forth miraculous cures; believers still bathe there today and Holywell has become known as the "Lourdes of Wales".
In 1138, Prior Robert of Shrewsbury moved the saint's remains to his abbey, later writing a "Life" - or biography - of Winefride, which was to prove instrumental in spreading her popularity.
In medieval times, she became the saintly equivalent of a superstar.
"Winefride, or Gwenfrewy as she is known in Welsh, is the only native female saint from Wales to have a substantial hagiographical dossier," says Prof Jane Cartwright, from the University of Wales Trinity St David.
"She was effectively a Welsh super saint whose cult extended beyond the Welsh border, since her relics were translated to Shrewsbury.
"She had two 12th Century Latin Lives and a 15th Century Welsh Life and she is one of the very few Welsh saints to make it into the Roman Martyrology.
Prof Cartwright, who is editing the medieval Welsh life of St Winefride for the Cult of Saints in Wales project, which aims to publish a digital edition of some 100 medieval Welsh-language texts on saints, adds: "In a sense her cult united England and Wales and she was deemed suitable to be venerated by royalty,"
At least six royal visitors - including Richard I, Edward IV and James II - have come to Holywell over the centuries.
By far the most famous visit was by Henry V in 1416, who, having placed himself under the spiritual protection of St Winefride before the previous year's Battle of Agincourt - where his 6,000 men faced a French army six times the size - walked from Shrewsbury to the shrine to thank her for his victory.
The precise date and route of the pilgrimage is unknown; in fact the only written record of it is in Latin, in the Chronicle of Adam of Usk so re-enacting the walk to commemorate its 600th anniversary has presented a challenge.
"There have been many attempts to work out the route," says walk organiser Ron Williams, from the Holywell Walkers are Welcome group.
"But when you think about it, there is only one way Henry V would have come.
"There weren't any roads except those the Romans had left and the Roman road comes to Llangollen from Shrewsbury, so that is most likely how he would have started off.
"On top of that he would have known that there was a Cistercian Abbey at Valle Crucis, so it's logical that he came there and if you look at a map, there's a direct line between Llangollen and Holywell so all we've done is put a walking route as near to that as possible.
"Of course we can't know it for sure but we think our route is more logical than those which have been put forward before.
"We have a good number of people walking the whole thing but we also want people to join in for the day so we've tried to make the walks easy to start and finish," adds Mr Williams.
The walkers - including one dressed as Henry V - will be welcomed into Holywell on 24 June.
The following day, the "King" will immerse himself in St Winefride's well.
An interdenominational service, an afternoon of talks on St Winefride and a medieval festival - complete with storytellers, jesters, archery and combat displays - are also part of the anniversary celebrations.
It is hoped the events will provide what festival organiser Mrs Owen claims is a "much-needed" boost for the Flintshire town.
"Holywell has been neglected," she said.
"It's like an unpolished diamond, a bit rough around the edges and it needs lots of little improvements.
"We want to get a much higher profile for the town with this - we want to really put it on the map."
Kerry Feather, project director of  St Winefride's Well, agreed: "We want the town and the well to benefit from the attention.
"We currently have around 35,000 visitors every year and we really would like to boost that number.
"Some people come here for healing but others just find it a place of peace and sanctuary, somewhere to spend time, whether it's in prayer or thought, in an oasis of calm in the middle of a very busy world."
The organisers of this year's pilgrimage re-enactment also want it to have a lasting legacy - they have applied for Lottery funding for the creation of a new pilgrim's trail from Shrewsbury to Holywell, complete with waymarkers.
"Walking a pilgrim's trail is not just a walk, it's a different experience altogether," said Mr Williams.
"I'm not religious but you're walking in places where people have walked for centuries and it gets to you.
"You think, 'Why were they here, how did they get here, how did they feel?'
"It's quite an emotional experience and you get a real sense of connection to the history of the places along the route."
Six centuries ago Henry V walked from Shrewsbury to Holywell in Flintshire, to give thanks for his famous victory over the French at Agincourt.