Former Celtic captain and manager Billy McNeill has passed away aged 79, the club have confirmed.
McNeill played his entire career for the club and captained the famous Lisbon Lions when they defeated Inter Milan to win the 1967 European Cup as well as leading them to nine successive titles and seven Scottish Cups and six League Cups.
He also managed the club in two spells winning the league title on four occasions and picking up four cups.
McNeill also managed Manchester City and Aston Villa.
A statement from his children on the Celtic website read: "It is with great sadness that we announce the death of our father Billy McNeill.
"He passed away late last night (Monday, April 22) surrounded by his family and loved ones. He suffered from dementia for a number of years and fought bravely to the end, showing the strength and fortitude he always has done throughout his life."
McNeill joined Celtic in 1957 from junior side Blantyre Victoria and holds the club record for most appearances with 822 over 18 seasons. The defender also won 29 caps for Scotland.
He was the captain of Jock Stein's all-conquering Celtic side of the late 1960s and early 70s before retiring in 1975 after winning his final trophy, the Scottish Cup.
He retained a strong association with the club throughout the rest of his life, becoming an ambassador in 2009.
Six years later a statue of McNeill holding aloft the European Cup was erected outside Celtic Park.
Celtic chief executive Peter Lawwell paid tribute on the club website, saying: "This is the saddest of days for the Celtic family, and also for the wider football world.
"We mourn Billy McNeill's passing and we send our thoughts and prayers to his family and friends, while we also give thanks for Billy's life and the incredible joy he brought to so many people as a Celtic player, a Celtic manager and a great Celtic man."
He had two spells as Celtic manager spanning nearly 10 years in total and won 31 trophies across his long association with the club.
Former Celtic striker Frank McGarvey, who McNeill signed from Liverpool in 1980, said: "It is a very very sad day.
"He was loved by all the players and you don't hear that about all managers. He was the captain of the first team to win the European Cup. As a manager, he was a great manager.
"He won a lot of trophies with Celtic on and off the pitch but not only that, he was a great person, a fantastic man. He would do anything to help you. He will be sadly missed."
Football pundit and former Celtic striker Chris Sutton tweeted: "Such heartbreaking news. Billy McNeill was an inspirational leader, a legend and a lion. Thoughts go out to his family and the Celtic family."
The family statement continued: "While this is a very sad time for all the family and we know our privacy will be respected, our father always made time for the supporters so please tell his stories, sing his songs and help us celebrate his life."
Additional reporting by PA