Bruno was tried for heresy by the Roman Inquisition on charges of denial of several core Catholic doctrines, including eternal damnation, the Trinity, the divinity of Christ, the virginity of Mary, and transubstantiation.

Historian Frances Yates argues that Bruno was deeply influenced by the presocratic Empedocles, Neoplatonism, Renaissance Hermeticism, and Book of Genesis-like legends surrounding the Hellenistic conception of Hermes Trismegistus.

[19] Such behavior could perhaps be overlooked, but Bruno's situation became much more serious when he was reported to have defended the Arian heresy, and when a copy of the banned writings of Erasmus, annotated by him, was discovered hidden in the monastery latrine.

[20] Bruno first went to the Genoese port of Noli, then to Savona, Turin and finally to Venice, where he published his lost work On the Signs of the Times with the permission (so he claimed at his trial) of the Dominican Remigio Nannini Fiorentino.

Given that Bruno dedicated various works to the likes of King Henry III, Sir Philip Sidney, Michel de Castelnau (French Ambassador to England), and possibly Pope Pius V, it is apparent that this wanderer had risen sharply in status and moved in powerful circles.

[citation needed] In April 1583, Bruno went to England with letters of recommendation from Henry III as a guest of the French ambassador, Michel de Castelnau.

His views were controversial, notably with John Underhill, Rector of Lincoln College and subsequently bishop of Oxford, and George Abbot, who later became Archbishop of Canterbury.

John Bossy has advanced the theory that, while staying in the French Embassy in London, Bruno was also spying on Catholic conspirators, under the pseudonym "Henry Fagot", for Sir Francis Walsingham, Queen Elizabeth's Secretary of State.

In 1591 he was in Frankfurt, where he received an invitation from the Venetian patrician Giovanni Mocenigo, who wished to be instructed in the art of memory,[44] and also heard of a vacant chair in mathematics at the University of Padua.

At the time the Inquisition seemed to be losing some of its strictness, and because the Republic of Venice was the most liberal state in the Italian Peninsula, Bruno was lulled into making the fatal mistake of returning to Italy.

[48] Among the numerous charges of blasphemy and heresy brought against him in Venice, based on Mocenigo's denunciation, was his belief in the plurality of worlds, as well as accusations of personal misconduct.

[52] The numerous charges against Bruno, based on some of his books as well as on witness accounts, included blasphemy, immoral conduct, and heresy in matters of dogmatic theology, and involved some of the basic doctrines of his philosophy and cosmology.

According to the correspondence of Gaspar Schopp of Breslau, he is said to have made a threatening gesture towards his judges and to have replied: Maiori forsan cum timore sententiam in me fertis quam ego accipiam ("Perhaps you pronounce this sentence against me with greater fear than I receive it").

On 17 February 1600, in the Campo de' Fiori (a central Roman market square), naked, with his "tongue imprisoned because of his wicked words", he was burned alive at the stake.

The records of Bruno's imprisonment by the Venetian inquisition in May 1592 describe him as a man "of average height, with a hazel-coloured beard and the appearance of being about forty years of age".

Alternately, a passage in a work by George Abbot indicates that Bruno was of diminutive stature: "When that Italian Didapper, who intituled himself Philotheus Iordanus Brunus Nolanus, magis elaboratae Theologiae Doctor, &c. with a name longer than his body...".

[60] In the first half of the 15th century, Nicholas of Cusa challenged the then widely accepted philosophies of Aristotelianism, envisioning instead an infinite universe whose center was everywhere and circumference nowhere, and moreover teeming with countless stars.

[63] Despite the widespread publication of Copernicus' work De revolutionibus orbium coelestium, during Bruno's time most educated Catholics subscribed to the Aristotelian geocentric view that the Earth was the center of the universe, and that all heavenly bodies revolved around it.

Among those who did were the Germans Michael Maestlin (1550–1631), Christoph Rothmann, Johannes Kepler (1571–1630); the Englishman Thomas Digges (c. 1546–1595), author of A Perfit Description of the Caelestial Orbes; and the Italian Galileo Galilei (1564–1642).

Some scholars follow Frances Yates in stressing the importance of Bruno's ideas about the universe being infinite and lacking geocentric structure as a crucial crossing point between the old and the new.

"[77] However, Otto Kern takes exception to what he considers Weinstein's overbroad assertions that Bruno, as well as other historical philosophers such as John Scotus Eriugena, Nicholas of Cusa, Mendelssohn, and Lessing, were pandeists or leaned towards pandeism.

[84] "It should not be supposed," writes A. M. Paterson of Bruno and his "heliocentric solar system", that he "reached his conclusions via some mystical revelation ... His work is an essential part of the scientific and philosophical developments that he initiated.

"[89] According to historian Mordechai Feingold, "Both admirers and critics of Giordano Bruno basically agree that he was pompous and arrogant, highly valuing his opinions and showing little patience with anyone who even mildly disagreed with him."

"[92] A. M. Paterson says that, while we no longer have a copy of the official papal condemnation of Bruno, his heresies included "the doctrine of the infinite universe and the innumerable worlds" and his beliefs "on the movement of the earth".

[93] Michael White notes that the Inquisition may have pursued Bruno early in his life on the basis of his opposition to Aristotle, interest in Arianism, reading of Erasmus, and possession of banned texts.

"[94] Frances Yates rejects what she describes as the "legend that Bruno was prosecuted as a philosophical thinker, was burned for his daring views on innumerable worlds or on the movement of the earth."

[97]Following the 1870 Capture of Rome by the newly created Kingdom of Italy and the end of the Church's temporal power over the city, the erection of a monument to Bruno on the site of his execution became feasible.

[99] A statue of a stretched human figure standing on its head, designed by Alexander Polzin and depicting Bruno's death at the stake, was placed in Potsdamer Platz station in Berlin on 2 March 2008.

Cosmos presents Bruno as an impoverished philosopher who was ultimately executed due to his refusal to recant his belief in other worlds, a portrayal that was criticized by some as simplistic or historically inaccurate.

[116] Hans Werner Henze set his large scale cantata for orchestra, choir and four soloists, Novae de infinito laudes to Italian texts by Bruno, recorded in 1972 at the Salzburg Festival reissued on CD Orfeo C609 031B.