"My father was fearless," says Rashid Ahmed, holding his dad's green and white jersey.
The precious family heirloom was brought back to India in 1936 after one of the most remarkable episodes in the history of the game.
The man he describes, Mohammed Salim, was a Calcutta league champion with Mohammedan Sporting Club and the first footballer from Asia to play in Europe.
His grandson Adil, who spoke along with his father, describes football as more than just a game: "In a way, sport was part of India's freedom struggle. They were playing in the last years of British rule and their performances showed that they were as good as their rulers".
He adds, "People like my grandfather gave a lot of hope to people in India."
One of Salim's biggest fans and closest friends, Mohammed Hasheem, worked as a bar tender on a steamship. It was him who persuaded the talented winger to try his luck in Scotland.
When Salim demonstrated his skills in a special trial at Celtic Park the coaches were quickly convinced they had a special talent. Club director Tom Colgan described him to the newspapers as "undoubtedly a player of fine natural gifts".
But there was another problem to be overcome, like most Indian footballers at the time he didn't wear boots.
His son Rashid says: "They had to get an official pass from the Committee for him to play with bare feet."
This was how Salim turned out for his first appearance against Galston on 28 August 1936, before 7,000 supporters in what was effectively a reserve match. Even without footwear, he was the man of the match.
The Scottish Daily Express nicknamed Salim the "Indian juggler" and reported that three of Celtic's goals in the 7-1 victory over the Ayrshire team came from his twinkling toes.
"He balances the ball on his big toe, lets it run down the scale to his little toe, birls it, hops on one foot round defender, then flicks the ball to centre, who has only to send it into goal."
Salim was picked to play again against Hamilton two weeks later, when he scored from a penalty.
"The barefooted Indian biffed the ball hard to the left of the goalkeeper who, although managing to get his hand to it, was totally unable to prevent it going into the net," reported the Daily Record.
The Indian winger's only protection from industrial Scottish defenders was a bandage.
The Daily Record carried a picture of him before the Hamilton match having his feet and ankles wrapped by Celtic's famous trainer Jimmy McMenemy.
His grandson Adil comments that this was a powerful image, "It would have been unimaginable here. This was before India was released from British rule and you would never see a white person touch the feet of a brown person".
The message from the dressing room at Parkhead was that everyone was equal when they pulled on a Celtic shirt.
Salim's final match for Celtic was a 3-2 victory over a Partick Thistle XI in a benefit match at Petershill Park, on 14 September. The Evening News reported that again, "Salim was the brightest player afield."
Celtic has seen enough to want to keep him, but just five days later he left on the same ship that had brought him to Glasgow. Along with his jersey, he carried a pair of white shorts and a gold watch as souvenirs.
Adil says that he was homesick, missing his family back home and Indian food.
Instead, it was fans of the all-conquering Mohammedan Sporting Club who got to enjoy his talents on their way to five successive Calcutta league titles.