Irish middle-distance runner Ciara Mageean, who won European gold and competed at two Olympic Games, has died aged 34, her family announced on Sunday.
"At 6:30am this morning, Ciara lost her battle with cancer surrounded by her loved ones," said a statement posted on the athlete's Instagram account.
Mageean's death comes just weeks after she married her long-term boyfriend in Belfast.
She had been receiving treatment for bowel cancer, revealing her diagnosis in July 2025 and subsequently disclosing that the disease was at an advanced stage.
Originally from Portaferry in County Down, Northern Ireland, Mageean established herself as one of Ireland's leading middle-distance runners, setting several national records.
She represented Ireland at the 2016 Rio Olympics and the Tokyo Games held in 2021.
Her greatest sporting achievement came in 2024 when she claimed the 1 500 metres title at the European Athletics Championships in Rome.
But an Achilles injury prevented her from competing at the Paris Olympics that year.
Mageean remained remarkably positive throughout her period of illness saying she was "continuing to find the joy in everyday" as she thanked people for their support following her diagnosis.
Speaking to the BBC in June, she said she was "grateful" for having a career "that many others didn't get to have".
Tributes poured in for Mageean, who also won a European silver and bronze in the 1500m (2022/2016 respectively) and finished second in the event in the 2022 Commonwealth Games.
"The country has lost a hero," the Olympic Federation of Ireland said in a statement.
"Beyond the medals, records and sporting accolades, Ciara will be remembered for her warmth, courage and tremendous strength of character," said Northern Ireland's First Minister Michelle O'Neill.
Irish Prime Minister Micheal Martin said he was "deeply saddened" by Mageean's "untimely passing".