John Eriugenia was the greatest thinker of the Dark Ages and put the Sun at the centre of the universe when everyone else believed that the Earth was at the heart of everything.
His theories, although almost forgotten, appear fresh and newly relevant today, Martin Counihan, of the University of Southampton, told the conference.
Although Eriugenia could not be described as a scientist - he made no measurements or observations - his thoughts were radically different to the deterministic beliefs of his day.
'He was highly rational, fiercely logical and didn't believe at all in superstition. During those so-called Dark Ages, when things were really quite bright, he was the star of the show,' Dr Counihan said.
Eriugenia was born in 820 in Ireland but emigrated to France as a young man for a position in the court at Lyons as a teacher and scribe. Dr Counihan said his friends were a 'boozy lot, talking and drinking into the evening'.
Because Eriugenia came to the conclusion that God and Heaven need not be physically above the stars, and the Devil and Hell were not necessarily located deep below ground, the Church accused him of being a pantheist and burnt his books.
Legend has it that Eriugenia finally met his death by being stabbed repeatedly with the writing quills of his students.
'You could say he lived by the pen and died by the pen,' Dr Counihan said.Reuse content