[10][11][12]: 05:06  O'Donnell and Art, however, alongside a guide sent to help them, continued south to the rural valley of Glenmalure, a rebel stronghold where they knew they would find safety.

The men undertook the lengthy journey from Dublin by foot in the middle of winter wearing wholly unsuitable 16th century clothing and footwear consisting of linens and tunics.

[9] In December of 1585, Art O'Neill made a successful escape from the castle and "hid for a time in the Wicklow mountains, but, attempting to head north to Ulster, he was recaptured before 20 February 1586", according to the Dictionary of Irish Biography.

[24] In an Irish Times article by Frank McNally, it was noted that the men began their escape through the vertical toilet chute of a garderobe at the top of an unspecified tower at Dublin Castle, after which they negotiated their way through the River Poddle, which was at that point used as a sewer.

[12]: 03:57 [26] Historian Jonathan Bardon contends that O'Neill organised the escape,[12]: 03:52  and McNally notes that Tyrone probably achieved this by bribing Dublin Castle staff.

Deep in the southern Wicklow Mountains one of the most secure of these areas was Glenmalure, which was the stronghold of Feagh McHugh O'Byrne, a powerful Chieftain, who carried out many raids within the Pale, and was a major thorn in the side of the Crown forces.

The River Poddle ran behind Dublin Castle, emptying into the Dubh Linn - Black Pool, which gave the town its name - nearby.

[11] Horses were supposed to have been provided to facilitate a faster and less tiring escape to Glenmalure, however these did not materialise,[25][32] and the group were forced to continue by foot notwithstanding Art's injury.

[25] Both Lughaidh Ó Cléirigh (O'Donnell's biographer) and the Annals of the Four Masters imply that Edward Eustace was the guide who escorted Hugh Roe from Dublin to Glenmalure.

"[34] At this time Ireland, along with the rest of Europe, was in the midst of a period known as the Grindelwald Fluctuation (1560s-1630s), part of what is now known as the Little Ice Age[12]: 08:43  which made the climate colder than usual.

Their guide (named Edward Hughes according to McGettigan),[12]: 10:40  continued onwards to Glenmalure valley to fetch help from O'Byrne,[14] who sent men back with food and beer to the location.

[12]: 10:40  An 1888 entry in Irish Monthly magazine summarised the scene that befell the rescuers:[40] When aid came to them from Wicklow, "their bodies," say the ancient Annals of the Four Masters, "were covered with white-bordered shrouds of hailstones freezing round them, and no life was found in their members."

Instead the reasoning goes that they veered left and went up into Glanreemore, whence they hit upon the Flags and could go no further [..] It must be said though that this steep ground is not a complete barrier – they weren't trapped by a wall of rocks, they could quite easily have climbed the back of the valley and regained their route.

The man must have had a terrible time getting to O'Byrne, but he did reach him at last, and the Wicklow chieftain, having heard his story, at once sent some of his people back with him to the spot where he had left his master and Art O'Neill.

After some time the rescuers were able to get him on to a horse and bring him safely to O'Byrne's stronghold amongst the Wicklow hills...[18] Some sources claim that O'Donnell and O'Neill brothers were the only people on record to have ever escaped from Dublin Castle during its period under English rule,[11] however it is known that at least one other person, Sir Edmund Butler of Cloughgrenan, also did so in November of 1569.

[46][1] From at least 1998 to 2007, an unofficial Art O'Neill Walk took place every year in January, starting at midnight from Dublin Castle, and was attended by people from "various hillwalking clubs around Ireland" as well as casual attendees who turned up on the night.

[34] The walk was conducted on a "no fee/no pre-entry" basis, and was primarily organised by, and for, members of the Irish Ramblers Club, led each year by Tom Milligan, an experienced hillwalker.

Indeed, on this Friday night, 5th January, 2007, four hundred and fifteen years after the escape of Red Hugh O’Donnell and Art and Henry O'Neill in 1592, over sixty walkers turned up for the challenge.

A "small group of regular volunteers from the Wayfarers Hillwalking Club" were noted to have provided a "welcome cup of soup and a slice of cake" to participants upon reaching the first one of these at Kilbride Army Camp at 3.30am, an isolated location at the foot of Seefin Mountain in County Wicklow.

[34] As daylight broke, the group ascended Glenreemore Brook to Art's Cross, before descending into Glenmalure valley and the river ford at Baravore, the traditional ending point of the walk.

[34] Pat Lynch, a member of Wayfarers Hillwalking Club, provided transport from the finish point "to anyone who required a lift to the train in Rathdrum" where they could get a ticket back to Dublin.

Hillwalkers normally don't like that arrangement of terrains, but the strangeness and unusual nature of the Walk, allied with the dramatic story it commemorates, makes it a journey everyone remembers with satisfaction, especially those who joined us from far-flung places like Sweden, Germany and the Sultanate of Oman.

[48][49] Other sources claim that the first iteration of the organised Challenge event (as opposed to the Walk) took place in January 2009,[50] at which it is known the racing bibs of competitors displayed the words "The Stuart Mangan Appeal".

"[58] Golf The 2011 event witnessed a 150% increase on 2009 numbers, with 500 registrants, including "a large international contingent" according to Outsider Magazine, with Irish, English, Scottish, Brazilian, American, German, Australian, New Zealand French, Italian, Spanish, Portuguese, Danish, Dutch and South African contestants having signed up.

[16] Since 2009, the event has grown, "owing to the hard work of Declan Cunningham and Gearóid Towey", into a "recognised annual sporting fixture on the Irish circuit".

[51] From 2018, the entrance fee was noted as €140 per person, with all proceeds "going directly to Dublin Wicklow Mountain Rescue Team's (DWMRT) operating costs".

[15] As of the 2016 event, the Belpark Triathlon Club, based in Rathfarnham, Dublin, wrote that the AON Challenge was "significantly over subscribed", with approximately 1 in 3 entrants securing a ticket.

[74] Before each race, participants are also briefed at the front of the castle with personal safety information, as well as rules aimed at minimising their damage to the Wicklow Mountains National Park through which they journey.

[1] The Challenge consists of 60 km that includes a mixture of city streets, country lanes, fire roads, mountain tracks, and open hillsides.

[47] From the January 2022 event onwards, however, the finish line was pushed back to the carpark at the Glenmalure Lodge pub, adding approximately 6 km to the pre-COVID route.