Paul Jeremy, a former secretary of the Association of History Teachers in Wales (AHTW), said: "Glan was a unique figure in Welsh educational history.
He presided over a remarkable period of academic scholarship but also gave great support and encouragement to those who revitalised the teaching of Welsh history in our schools.
"He recognised that if they didn't get Welsh history taught effectively in schools then all the academic studies in the world would stay on dusty shelves."
Sir Glanmor was born in Dowlais, near Merthyr Tydfil, the only child of working-class parents. He was educated at Cyfarthfa Castle school and Aberystwyth university. He spent 40 years at Swansea university, 25 as professor of history.
Other posts included 10 years as vice-president at Aberystwyth university and a six-year tenure as the BBC's national governor for Wales. A bilingual scholar, he was knighted in 1995 for his services to the history, culture and heritage of Wales.
Ralph Griffiths, professor of medieval history at Swansea university, and a former colleague, said: "He was equally comfortable talking to an intellectual Oxford audience as he was giving a talk to a local community history group. He thought history was a subject that should be accessible to all."
Sir Glanmor became the first president of the AHTW at its inception 17 years ago. The organisation represents all history teachers, from university academics through to primary school teachers. Its current chair Peggy George said: "He was able to captivate all age groups. I don't think any of us thought of him as an old man because he was so dynamic."
Just two weeks before he died, Sir Glanmor gave a lecture at All Souls College, Oxford, to mark the retirement of Rees Davies, professor of medieval history.