It's unlikely that the sun was shining quite so brightly this week 1,000 years ago when Brian Boru was cut down.
But yesterday, as more than 500 Vikings and Irish natives descended on Dublin to re-enact the fateful Battle of Clontarf, it was almost too hot to wear heavy armour and bull-horn helmets.
The largest ever living history battle re-enactment in Ireland – staged at the Battle of Clontarf Festival – was not so much blood and gore, but sunburn and ice-cream cones.
An estimated 30,000 people flocked to the event, as the spring sunshine beamed down on St Anne's Park in Raheny for the first day of festivities.
More than 60,000 visitors are expected to attend the spectacular clashes between Irish and Viking armies which feature re-enactors with a love for ancient battle from all around the world.
"I think it's absolutely brilliant, I was dying to come here because I'm half-Swedish and half-Irish – so I love the whole Celts and Vikings thing," Tania Stewart told the Sunday Independent.
"I really wanted to show my son the whole battle re-enactment. The weather is beautiful, and it's free, what more can you ask for? It's really well put together," Tania added.
Along with the twice-daily battle re-enactments, the festival includes tableaus of Viking life in a medieval village with more than 80 tents, skills and weapons demonstrations, a mounted display, a Viking longboat, falconry, archery, food, music and entertainment.
Joe O'Neill and his children, three-year-old Jack and one-year-old Reilly, travelled to the festival from Lucan.
"They're having a ball – but to Jack they're all just pirates – not Vikings at all," laughed Joe.
"It is a stunning event. I'm from Clontarf, but I haven't been down this way in a long time, it's great."
Others were happy to see the 1000th anniversary of the historic battle being marked by Dublin City Council.
"It's great to see that there is something on to commemorate the Battle of Clontarf," said Gareth Feeney from Baldoyle, who was at the festival with his partner Rachel and their six-month-old daughter Sarah. "It very busy though," Gareth added. "It's a bit difficult to get in to see everything, but that's just the way things are.
"I don't think they expected so many people, but because of the weather loads have come out."
One of the festival's re-enactors, Russ Scott, has been travelling the world taking part in historical battle re-enactments for 27 years.
"I did research on the Battle of Clontarf to put as much into the battle as we could and, with the 500 warriors we have on hand this weekend, we can bring in more realistic elements," he said.
The re-enactments are not for the faint-hearted – there may not be any blood but the real weapons and strategic, well-rehearsed fighting techniques leave little room for error.
"Every group is here by invitation and we train to look good and fight well, but we don't hurt people, although accidents do happen, but not very bad ones!" Russ added.
Nuala Collins, of Dublin City Council, was delighted with yesterday's turnout.
"We have been blessed with the weather this weekend and the Viking village has really brought the whole event to life, the re-enactors have all been camping out here since Tuesday," she explained.
"St Anne's Park is in very close proximity to where the Battle of Clontarf took place a thousand years ago, so it's of huge significance and gives the story back to the people," Ms Collins added.