The son of a soldier from Nola in Italy, Bruno entered the Dominican Order in 1565 but was forced to leave in 1576 for unspecified reasons. The following 15 years were spent traveling in France, England, and Germany before visiting Venice in 1591 where he was arrested and handed over to the Inquisition (1592). He was extradited by the Roman Inquisition in 1593. As details of the trial have been destroyed it is no longer known which eight heretical propositions he refused to recant. The results of his action are not however in any doubt: he was burned at the stake.

The exact role of Bruno in 16th-century intellectual history remains a matter of considerable controversy and he was clearly a man of many parts. He was first an expert on the art of mnemonics (memory), a renaissance ‘science’ long extinct, and he was also involved with a revival of the occult mystical philosophical system of hermeticism. More importantly Bruno was also a keen supporter of the heliocentric system of Nicolaus Copernicus and in his Cena de le Ceneri (1584; The Ash Wednesday Supper) added to some rather implausible arguments in defence of Copernicus's claims for the infinity of the universe. His championing of the then unorthodox heliocentric theory was certainly considered heretical and his unhappy end may well have influenced Galileo's actions before the Inquisition.