Legend maintains St Patrick tried to kill off the devil's mother on the summit of Croagh Patrick, Ireland's Holy Mountain. He had chosen a beautiful location, a majestic quartzite cone, overlooking Clew Bay and much of the surrounding Co Mayo landscape.
Although the good saint failed, he did manage to briefly trap her in a lake. She escaped that time. But he did later finish her off in Lough Derg.
The devil was however far from the minds and intentions of the many thousands who yesterday walked, scrambled, staggered and toiled the famous mountainside.
This is one of the great pilgrimage routes. Evidence of the enduring power of belief was there to be seen in some of the faces of men and women intent on performing the rituals of pilgrimage; prayer and a set number of laps about each of the stations. For many, many more, though, it was a good day out.
From the early hours until late in the afternoon humanity moved as one.
Walking the Reek is a tradition motivated by a devotion to St Patrick as well as a sense of the occasion. Barefoot penitents arrived, stoic and oblivious of the sharp stones. Some held rosary beads.
Others appeared to approach the climb more with the attitude of endurance athletes than aspiring martyrs. One man from Laois said it was his 10th year "and I've been getting faster, it's mind over matter". Which was just as well - the matter in question, his feet, looked in need of professional attention.
By 5 a.m. crowds had replaced individual groups. It was already a bit too busy for anyone who prefers their mountains big and empty. But the good humour compensated for the bustle.
In 1940, the poet Patrick Kavanagh correctly read the atmosphere that prevails on Croagh Patrick. Celebration not penance sets the tone.
For all the visitors, there is also something distinctly local. Greetings are exchanged, a man was asked had his gun dog's pups arrived, while a woman struggling to open a bottle of water stopped a young lad walking by, would he open it for her, "and is your Mam back from holidays?"
We walked on, certainly among the early birds, but surprised by the numbers already on their way down.
"We went up at 2.30 last night," said a small woman in a large yellow rain coat. "Never again, we could see nothing and I thought the cold would kill me."
Her companion, a man whose demeanour was one of resignation, said: "I've been thinking about having tea, just a cup of tea. Nothing else."
It seemed a long way to have gone simply to ponder the virtues of tea. But people are different. Bent by age, an elderly man dressed in fine leather brogues and a tweed suit, inched his way along the stony track.
In contrast to his immense effort was the number of young men in Roscommon football shirts, giddy with the previous day's victory, who jostled each other, with a few falling down hard on the stones.
Some people gave the impression of having completed the route at least once a day all their lives, others looked as if they were attempting Everest. It is an easy walk.
Daylight was followed for a while by bright sun and strong breeze. As always on a mountainside, a lone shoe lay abandoned on the path. Sadly, so too was litter in abundance.
A rake in evening jacket, black tie still neatly knotted, announced to his dishevelled female companions, one of whom laughed endlessly, "this was not one of my better ideas".
For every stroller carrying a bottle of water, there were at least three storm trooper-types in full mountaineering gear, complete with back packs, ski poles, climbing wear and expressions of determination.
A little donkey made his way up, for him it was work not pilgrimage.
Traders were confident of competing with prayer for the attention of the faithful.
At St Benen's Bed, the first station, several travellers kept count as they walked seven times around the cairn. They had driven up from Mullingar to mark a tradition as well as the end of summer.
As the summit came closer, the drizzle seemed heavier. Suddenly it was darker, almost misty. The last time we climbed Croagh Patrick, there was only a handful of us amateur photographers busily snapping Clew Bay in full sunshine. But it had not been on Reek Sunday. Yesterday, the summit resembled a railway station alive with damp figures looking more like refugees than penitents.
Yet people of all ages filed around St Patrick's Bed fulfilling the prayer requests. Elsewhere, individuals sank to their knees closed their eyes and communicated with their God. Mobile phones also had their turn.
Back down the track to wait and watch. Teenage girls seemed to rest every few hundred yards, while a Bart Simpson-like boy complained to his father. "You'll walk up this mountain, my lad, like your sisters, or you'll regret it". The lad sighed: "I'm already regretting it."
Free bibles were being handed out. A middle aged woman took one and looked up at the distant cone. "I've climbed this a few times. It is getting harder, but here goes."