Alex Ferguson retired as Manchester United manager because of stress, according to former England boss Fabio Capello.
Fergie called it quits on Wednesday after nearly 27 years in charge at Old Trafford, where he won an incredible 38 trophies.
Everton chief David Moyes will succeed the Scot at the end of the season.
Capello admits he was shocked by the timing of the decision, but revealed Fergie’s choice was down to the pressures of modern-day football.
The Italian said: “I met him a few months ago at the England Sports Centre and he told me he would carry on, so the news of his retirement surprised me.
“I called him yesterday and he told me he has decided to go now because there is too much stress nowadays.
“Always having to win something is very challenging, and he told me he wanted to go around the world with his wife.
“His secret is amazing. To have that strength and ability to change things and improve every year, and always have the same desire to win.”