They were just 11 men - all but one born and raised within 30 miles of Glasgow.

All of them had grown up with a ball at their feet. Little did they know that one day they would write their names into football folklore and become Celtic legends.

These were the lads who had played keepy-uppy in back greens or around the tenements, who shared a dream to play for the team they loved in front of fans who loved them.

On May 25, 1967, the dream came true. On a pitch more than a thousand miles away, in front of a roaring sea of green and white, 11 men became lions.

Celtic's European Cup victory that season against Inter Milan could be considered the greatest feat by a British team in Europe.

It paved the way for other British victories, without the big money transfer fees or today's tabloid transgressions.

These were the Bhoys who wore their numbers sewn on to their shorts, whose winning goal led to ceilidh dancing on a Portuguese pitch and made them heroes in the hearts of Celtic fans for decades to come.

One of those fans was David Frier, who, along with fellow fan Pat Woods, has released a book on Celtic's European Cup triumph.

David was just eight when the Lisbon Lions played but their legacy led him on an investigative journey which has uncovered some rare photographs and untold stories of the victory.

"We've found images that as far as we know have never before been published in the UK," says David.

His absolute favourite find, he says, is one striking image of a lady dressed in a demure tartan skirt ceilidh dancing on the pitch after the winning goal.

"I absolutely love it," he says. "It captures the feeling of that day so well."

David and Pat have spent four years carrying out research to produce their book, We'll Always Have Lisbon: Celtic's Glory Year 1967.

Their journey has taken them into archives across Europe to reveal new perspectives from players, from football museums to the Portuguese police, and even the match referee, who died three weeks after David met him.

In what can be considered to be his final interview about the game, Kurt Tschenscher said the day had filled him with happy memories.

"I got to him just in time and had a very pleasant chat with him," says David. "He said he thought Celtic thoroughly deserved to win, especially in the second half.

"He was happy to think people in Scotland still cared about hearing of the game 50 years later."

David and Pat also explore the prospect that the cup final might been played elsewhere.

"If it had, we would have had to look for a very different nickname," says David. "Or at least not be able to guarantee that it would have ended up the way it did."

They also explore the personal nature of the contest between the two managers, Jock Stein and Helenio Herrera.

"Celtic were considered to have a very attacking team and a breath of fresh air to the game, while Inter Milan were considered a bit defensive," says David.

"But there is actually more in common between the men than you might think."

The authors have discovered quirky anecdotes, such as the rather unusual move by a Portuguese newspaper in the run up to the game.

"One thing that amused me was that on the very morning of the final, a Portuguese newspaper published precise details of the Celtic players' hotel rooms and encouraged readers to phone them up for a chat," says David laughing.

"You simply can't imagine that happening today."

The pair say they are "delighted" their book has been published, admitting to being avid Celtic fans and cheerfully "a bit geeky" in their quest for knowledge on the club.

"It has been a great experience," says David. "I've heard copies are at Celtic Park and in other club book shops."

The original team have been in the minds of fans even more so this month with the passing of one of their legendary players.

Tommy Gemmell, who died earlier this month at the age of 73, scored the equaliser in Lisbon before Stevie Chalmers' winner as Celtic came from a goal behind to beat Inter Milan 2-1.

It earned the full-back legendary status at the Glasgow club.

In response to the sad news of his passing, former Celtic favourite Kenny Dalglish backed a call made earlier this month by Brendan Rodgers for a formal recognition of Jock Stein's team.

It's a move akin to David and Pat's own feelings, which prompted their own written historical tribute to the men who became lions.

As Kenny Dalglish told reporters last week: "They know what they've done. Everyone knows what they've done.

"It doesn't matter if it's 50 years or 100 years. They will still be totally revered - and rightly so."