Golf legend Seve Ballesteros has died at the age of 54, his family have confirmed via his official website.
The Spaniard, who won five majors and was instrumental in growing golf's popularity, passed away at 0110 BST this morning due to respiratory failure.
Ballesteros had fought a long battle with a neurological condition since being diagnosed with a brain tumour in 2008.
The family's statement at www.seveballesteros.com read: "At 02:10 hours [Spanish time], Seve Ballesteros - accompanied by his family at his home in Pedrena - died due to respiratory failure.
"The family appreciates all the expressions of support and affection they have received since Seve was admitted on October 5, 2008 at the Hospital Universitario La Paz in Madrid.
"At the same time, please respect our privacy at such a painful time. Thank you very much."
Ballesteros, who announced his retirement from golf in 2007, collapsed at Madrid Airport in October 2008 and two days later came confirmation that he had a brain tumour.
He underwent an initial 12-hour operation, but further surgery was necessary before he was well enough to return home and begin chemotherapy and radiotherapy treatment.
"I am very motivated and working hard, although I am aware that my recovery will be slow and therefore I need to be patient and have a lot of determination," he said at the time.
"For these reasons I am following strictly all the instructions that the doctors are giving me. Besides, the physiotherapists are doing a great job on me and I feel better every day."
After a second course of chemotherapy at Madrid's La Paz Hospital in February 2009 he said on his website: "The results of the check-up were really positive, better even than the first ones."
Two more courses followed and four months later Ballesteros made his first public appearance, saying it was "a miracle" to be alive.
In December 2009 he appeared on television to receive the BBC's Lifetime Achievement Award at the Sports Personality of the Year event from his former Ryder Cup partner - and now captain - Jose Maria Olazabal.
He won the Open three times, the Masters twice and played an inspirational role in the Ryder Cup, helping Europe to lift the trophy in 1985, 1987, 1989 and 1995 before captaining them to another victory at Valderrama two years later.
Ballesteros turned professional in 1974 at the age of 16 and made his first huge impact two years later by finishing second in the Open alongside Jack Nicklaus at Royal Birkdale.
His first major title came in the 1979 Open at Royal Lytham, he then became Masters champion in 1980 and 1983 and lifted the Claret Jug again at St Andrews in 1984 - his greatest moment really - and back at Lytham in 1988.
After a total of 87 tournament wins, his retirement came following years of battling an arthritic back and knee problems.
He was planning a farewell appearance for British fans at last year's Open at St Andrews - not in the main event, but in the four-hole Champions Challenge - but was not well enough to travel.
Only last month Phil Mickelson decided on a Spanish menu for the Champions Dinner at The Masters at Augusta in honour of Ballesteros.
European Tour chief executive George O'Grady said: "This is such a very sad day for all who love golf.
"Seve's unique legacy must be the inspiration he has given to so many to watch, support, and play golf, and finally to fight a cruel illness with equal flair, passion, and fierce determination.
"We have all been so blessed to live in his era. He was the inspiration behind The European Tour."
The flags at Real Club de Golf El Prat will be flown at half-mast in him memory for today's third round of the Spanish Open, while the players will wear black ribbons and there will also be a minute's silence.
Bernard Gallacher, who captained Ballesteros in three Ryder Cups between 1991 and 1995, said: "He felt it was his duty as the best player in the world to inspire the European team.
"When I became captain in 1991 he was still one of the best players in the world and he former a formidable partnership with Olazabal, virtually unbeatable."
Ballesteros also delivered an inspirational message to Colin Montgomerie's victorious team at Celtic Manor last year, and Gallacher added: "Seve's best golf was played in the 1980s but he was still inspiring this new generation of golfers - the Martin Kaymers, the Ross Fishers, we've heard from Lee Westwood how as a young boy he would watch Seve and everyone would want to copy and emulate Seve.
"Every European Tour player today should thank Seve for what they're playing for. America had Jack Nicklaus and Arnold Palmer - Seve was our Arnold Palmer and Jack Nicklaus rolled into one.
"You can't speak too highly of him, Seve was Europe's best ever player."
Ballesteros' former caddie Billy Foster remembers him as "an absolute gentleman, the ultimate warrior."
Foster added on Sky Sports News: "There's not many players I've worked for in my time that have that aura about them. It was a special time - I was probably 25 years old, I'd caddied for maybe 10 years, and I got the ultimate dream chance of working for an absolute superstar."