Mr Fenton, 57, led the organisation, dedicated to preserving the memory of Scottish patriot William Wallace, for four years. He lived in Greengairs, North Lanarkshire, and died at 8.30pm on Sunday at Monklands Hospital. He was diagnosed with bowel cancer in January.
His widow, Jean, 55, said: "Duncan was the best man in the world, a true Scotsman who would have dropped everything and done anything for anyone.
"He showed such bravery in his battle. He was loved by so many people." Friends and Society members described Mr Fenton as an "inspiration", and a "man of integrity, love and humour".