Born out of the jogging boom of the early 1980s, the Belfast City Marathon first hit the roads in 1982 and has been gathering pace ever since.
The hugely popular event was first run on May 3, 1982, driven by the charismatic head of athletics in Northern Ireland, Les Jones.
Over 3,000 runners took part in the inaugural edition, with 2,171 runners completing the 26.2-mile route which started at the old Maysfield Leisure Centre and included two laps of a specially-designed circuit.
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In the 40 years since, the event has savoured success, endured controversy and suffered tragedy, but continues to evolve into a global attraction now featuring a five-person team relay, walk and fun run.
One man who has charted the Belfast Marathon's growth and transformation over those four decades is John Glover.
He has watched the event adapt from its formative years in the 1980s to becoming the biggest participatory sporting event in Northern Ireland.
Current vice-president and former President of Athletics NI, John can recall the first running in 1982 and some of the early teething problems - including one runner being followed by a hearse.
"In the first year the race attracted 3012 entries of whom 2171 survived the distance and the cold, windy conditions which the previous night had brought down trees and caused chaos on the railways," said John, who has previously worked on the design and course measurement of the Belfast Marathon route.
"The race began at what was then Maysfield Leisure Centre adjacent to what is now Lanyon Railway Station, and was a two lap affair. The days of traffic management and closed roads were years away and one unfortunate runner found himself crossing the Albert Bridge at the end of the first lap followed by a hearse. The race was won by local man Greg Hannon.
"Strong criticism of the two lap course led to a revamp the following year to a single lap taking in a much greater geographical and political area of the city, and indeed beyond. This was the first of what would be a long list of changes minor and major to the marathon route with the 2022 edition being the thirteenth metamorphosis."
John also recalls how bomb scares in Belfast forced two last-minute detours.
"In 1999 a suspect device was discovered in time for a quick minor diversion, however in 2005 the runners were well on their journey when news of a device at Gideon’s Green underpass was relayed to the organisers," said John, who was awarded a BEM for Services to Athletics in 2020.
"Thankfully a bit of quick thinking by a PSNI motorcycle outrider saved the day. He managed to direct the runners further up the road, through a park and down a grassy slope back on to Loughshore to join the route.
"Unfortunately this was not before a handful of runners had already passed what thankfully turned out to be a hoax device, and for those detoured it meant an additional 1400 metres of torture."
John added: "You always hope that all will run smoothly but nothing is guaranteed. There have been hiccups during the previous 39 editions of the event including, in 1987, a false start.
"Another late bomb scare was only picked up by event director, Les Jones, seconds before the start, too late to stop the then Lord Mayor Sammy Wilson firing the gun and sending the twitchy field heading up the hill towards the train station.
"Thankfully the stewards were quick to form a barrier across the road and, after a wait of half an hour, Sammy was allowed to fire his gun again.
"In 1986 the race organisers faced the embarrassment of having to compensate the runner up Andy Holden after he had, not once but, twice followed the lead car which lost its way.
"Sadly this situation was replicated in 2019 when the entire field were similarly detoured twice by the lead car adding over 500 metres to their journey.
"In recent years the event has begun to recapture and indeed surpass the numbers from the early 80’s. In many ways the event has become a victim of its own success."
After the initial jogging phenomenon started to lose its impetus, marathon numbers began to drop.
Organisers of the Belfast City Marathon had to galvanise the event with fresh ideas, so in 1989 the five-person Team Relay was introduced to be followed in later years by the Walk and Fun Run.
Other innovative changes were made to the route, while three years ago the event moved from the Monday to Sunday.
"In 2003 the race start was moved to the iconic position directly in front of Belfast City Hall," John added.
"Three years later another major change took place as the stretch on the East of the City out to Holywood and back via Airport Road was replaced by a long haul up the Antrim Road in the North.
"In recent years both the competitors and the sponsors had had enough of this muscle sapping climb and subsequent steep drop and discussion took place to design a radically new course and to move the race to a Sunday.
"For this plan to come to fruition took two years of intensive negotiation and diplomacy before on Sunday, May 5, 2019 the Belfast City Marathon started beneath the backdrop of Parliament Buildings at Stormont.
"Both the change in route and day were generally warmly welcomed and while some regretted the breaking of the sanctity of the Sabbath the vast majority of the churches along the route got actively involved by providing refreshment and entertainment for the runners."
John - who ran his first marathon in 1981 and since then has competed in Belfast, Antrim, Paris, Caen, Barcelona, and Dublin - says a large part of the Belfast City Marathon's success is down to the volunteers who help the event run smoothly on the day.
"The demands made on the organisers by the need for closed roads, and health and safety and the much greater demands made by the modern running community has created major difficulties for the organisers. A major requirement is volunteers to ensure that the runners experience on the day is a smooth and enjoyable one," he said.
"Having someone on every street junction on the 26 miles 385 yards course requires hundreds of willing bodies as does the manning of the drinks stations and relay changeovers.
"Add to that the logistics of getting athletes their race numbers and arranging transport for relay runners to and from changeovers and the task reaches gigantic proportions, efforts sadly not always recognised by participants. Thankfully the Northern Ireland public do respond."
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