(1548 Nola – Rome, February 17, 1600) was an Italian
philosopher, priest, cosmologist, and occultist. Bruno
is known for his system of mnemonics based upon
organized knowledge and as an early proponent of the
idea of an infinite and homogeneous universe. Burned at
the stake as a heretic by the Roman Inquisition, Bruno
is often seen as the first martyr to the cause of
Born in Nola (in Campania, then part of the Kingdom of Naples) in
1548, he was originally named Filippo Bruno. His father was Giovanni
Bruno, a soldier. At the age of eleven he traveled to Naples to
study the Trivium. At 15, Bruno entered the Dominican Order, taking
the name of Giordano from Giordano Crispo, his metaphysics tutor. He
continued his studies, completing his novitiate, and becoming an
ordained priest in 1572.
He was interested in philosophy, and was an expert on the art of
memory; he wrote books on mnemonic technique, which Frances Yates
contends may have been disguised Hermetic tracts. The writings
attributed to Hermes Trismegistus had played an important role in
the Renaissance Neoplatonic revival. At that time they were thought
to date uniformly to the earliest days of ancient Egypt and to
encode a form of "pristine wisdom" ("prisca philosophia").
now believed to date mostly from about 300 A.D. and are associated
Woodcut illustration of one of Giordano Bruno's mnemonic devices:
the spandrels are the four classical elements: earth, air fire, water
While the Hermetic Tradition was a major influence on Bruno, he
also absorbed and developed the heliocentric ideas of Copernicus.
Other significant influences included Thomas Aquinas, whose works he
had to study in depth as a novice and for whom he always expressed a
curiously deep admiration (), Averroes, whose idea of a universal
mind resonates through Bruno's work, Duns Scotus, the Renaissance
Neoplatonist Marsilio Ficino, and, last but certainly not least,
Nicholas of Cusa's ideas on infinity and indeterminacy, particularly
the idea of an infinite universe where Earth has no special place.
Bruno developed a pantheistic hylozoistic system, essentially
incompatible with orthodox Christian Trinitarian beliefs.
In 1576 he left Naples to avoid the attention of the Inquisition. He
left Rome for the same reason and abandoned the Dominican order. He
travelled to Geneva and briefly joined the Calvinists, before he was
excommunicated, ostensibly for slandering the philosophy professor
Antoine de la Faye. After Bruno apologized his excommunication was
revoked, but in autumn 1579, deeply disappointed by Calvinist
intolerance, he left for France.
He went first to Lyon, but he could not find work there and in late
1579 he arrived in Toulouse, at that time a Catholic stronghold,
where he obtained a position as lecturer of philosophy. After the
bitter experience in Geneva, he also tried to revert to mainstream
Catholicism, but he was denied absolution by the Jesuit priest that
After religious strife broke out in
Toulouse in summer 1581, he moved to Paris, where first he held a
cycle of thirty lectures on theological topics. At this time, he
also began to gain fame for his prodigious memory. Bruno's feats of
memory were based, at least in part, on his elaborate system of
mnemonics, but some of his contemporaries found it easier to
attribute them to magical powers. His talents attracted the
benevolent attention of the king Henry III, who supported a
conciliatory, middle-of-the-road cultural policy between Catholic
and Protestant extremism.
In Paris he enjoyed the protection of his powerful French patrons.
During this period, he published several works on mnemonics, a.o.
"De umbris idearum" (The Shadows of Ideas, 1582), "Ars Memoriae"
(The Art of Memory, 1582), "Cantus Circaeus" (Circe's Song, 1582),
based on his model of organised knowledge, opposed to that of Petrus
Ramus. In 1582 Bruno also published a comedy summarizing some of his
philosophical positions, titled "Il Candelaio" ("The Torchbearer").
In April 1583, he went to England with letters of recommendation
from Henry III, working for the French ambassador, Michel de
Castelnau. There he became acquainted with the poet Philip Sidney
and with the Hermetic circle around John Dee. He also unsuccessfully
sought a teaching position at Oxford, where however he held
lectures. His views spurred controversy, notably with John
Underhill, Rector of Lincoln College and from 1589 bishop of Oxford,
and George Abbot, who later became Archbishop of Canterbury, who
poked fun at Bruno for supporting “the opinion of Copernicus that
the earth did go round, and the heavens did stand still; whereas in
truth it was his own head which rather did run round, and his brains
did not stand still.”() and who reports accusations of
plagiarising Ficino's work. Still, the English period was a fruitful
During that time Bruno completed and
published some of his most important works, the "Italian Dialogues",
including the cosmological tracts "La Cena de le Ceneri" (The Ash
Wednesday Supper, 1584), "De la Causa, Principio et Uno" (On Cause,
Prime Origin and the One, 1584), "De l'Infinito Universo et Mondi"
(On the Infinite Universe and Worlds, 1584) as well as "Lo Spaccio
de la Bestia Trionfante" (The Expulsion of the Triumphant Beast,
1584) and "De gl' Heroici Furori" (On Heroic Frenzies, 1585).
Some of the works that Bruno published
in London, notably the "The Ash Wednesday Supper", appear to have
given offense. It was not the first time, nor was it to be the last,
that Bruno's controversial views coupled with his abrasive sarcasm
lost him the support of his friends.
In October 1585, after the French embassy in London was attacked by
a mob, he returned to Paris with Castelnau, finding a tense
political situation. Moreover, his 120 theses against Aristotelian
natural science and his pamphlets against the Roman Catholic
mathematician Fabrizio Mordente soon put him in ill favor. In 1586,
following a violent quarrel about Mordente's invention, "the
differential compass", he left France for Germany.
Woodcut from Articuli centum et sexaginta adversus huius tempestatis
mathematicos atque philosophos,
In Germany he failed to
obtain a teaching position at Marburg, but was granted permission to
teach at Wittenberg, where he lectured on Aristotle for two years.
However, with a change of intellectual climate there, he was no
longer welcome, and went in 1588 to Prague, where he obtained 300 taler from Rudolf II, but no teaching position. He went on to serve
briefly as a professor in Helmstedt, but had to flee again when he
was excommunicated by the Lutherans, continuing the pattern of
Bruno's gaining favor from lay authorities before falling foul of
the ecclesiastics of whatever hue.
1591 found him in Frankfurt. Apparently, during the Frankfurt Book
Fair, he received an invitation to Venice from the patrician
Giovanni Mocenigo, who wished to be instructed in the art of memory,
and also heard of a vacant chair in mathematics at the University of
Padua. Apparently believing that the Inquisition might have lost
some of its impetus, he returned to Italy.
He went first to Padua, where he taught briefly, and applied
unsuccessfully for the chair of mathematics, that was assigned
instead to Galileo Galilei one year later. Bruno accepted Mocenigo's
invitation and moved to Venice in March 1592. For about two months
he functioned as an in-house tutor to Mocenigo. When Bruno announced
his plan to leave Venice to his host, the latter, who was unhappy
with the teachings he had received and had apparently developed a
personal rancour towards Bruno, denounced him to the Venetian
Inquisition, that had Bruno arrested on May 22, 1592.
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. Bruno defended himself
skillfully, stressing the philosophical character of some of his
positions, denying others and admitting that he had had doubts on
some matters of dogma.
The Roman Inquisition, however, asked
for his transferal to Rome. After several months and some quibbling
the Venetian authorities reluctantly consented and Bruno was sent to
Rome in February 1593.
The monument to Bruno
in the place he was executed,
Campo de' Fiori in
Close-up of the
Trial and death
In Rome he was imprisoned for seven years during his lengthy trial,
lastly in the Tower of Nona. Some important documents about the
trial are lost, but others have been preserved, among them a summary
of the proceedings that was rediscovered in 1940.  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.
Luigi Firpo lists them as follows: 
Holding opinions contrary to the
Catholic Faith and speaking against it and its ministers.
Holding erroneous opinions about
the Trinity, about Christ's divinity and Incarnation.
Holding erroneous opinions about
Holding erroneous opinions about
Transubstantiation and Mass.
Claiming the existence of a
plurality of worlds and their eternity.
Believing in metempsychosis and
in the transmigration of the human soul into brutes.
Dealing in magics and
Denying the Virginity of
Bruno continued his Venetian defensive
strategy, which consisted in bowing to the Church's dogmatic
teachings, while trying to preserve the basis of his philosophy. In
particular Bruno held firm to his belief in the plurality of worlds,
although he was admonished to abandon it. His trial was overseen by
the inquisitor, Cardinal Robert Bellarmine, who demanded a full
recantation, which Bruno eventually refused. Instead he appealed in
vain to Pope Clement VIII, hoping to save his life through a partial
The Pope expressed himself in favor of a
guilty verdict. Consequently, Bruno was declared a heretic, handed
over to secular authorities on February 8, 1600. At his trial he
listened to the verdict on his knees, then stood up and said:
"Perhaps you, my judges, pronounce
this sentence against me with greater fear than I receive it."
A month or so later he was brought to
the Campo de' Fiori, a central Roman market square, his tongue in a
gag, tied to a pole naked and burned at the stake, on February 17,
The conflicts over
All his works were placed on the Index Librorum Prohibitorum in
1603. Four hundred years after his execution, official expression of
"profound sorrow" and acknowledgement of error at Bruno's
condemnation to death was made, during the papacy of John Paul II.
Attempts were made by a group of professors in the Catholic
Theological Faculty at Naples, led by the Nolan Domenico Sorrentino,
to obtain a full rehabilitation from the Catholic authorities.
In 1885 an international committee for a monument to Bruno on the
site of his execution was formed , including Victor Hugo, Herbert
Spencer, Ernest Renan, Ernst Haeckel, Henrik Ibsen and Ferdinand
Gregorovius.   The monument was sharply opposed by the
clerical party, but was finally erected by the Rome Municipality and
inaugurated in 1889.
Some authors have characterized Bruno as a "martyr of science",
making a parallel to the Galileo affair. They assert that, even
though Bruno's theological beliefs were an important factor in his
heresy trial, his Copernicanism and cosmological beliefs also played
a significant role for the outcome. Others oppose such a fatal role
of the Copernican system for Bruno, and claim the connection to be
exaggerated, or outright false.  
The Vatican webpage about Bruno's trial provides a different
"In the same rooms where Giordano
Bruno was questioned, for the same important reasons of the
relationship between science and faith, at the dawning of the
new astronomy and at the decline of Aristotle’s philosophy,
sixteen years later, Cardinal Bellarmino, who then contested
Bruno’s heretical theses, summoned Galileo Galilei, who also
faced a famous inquisitorial trial, which, luckily for him,
ended with a simple abjuration." 
The cosmology of
According to Aristotle and Plato, the universe was a finite sphere.
Its ultimate limit was the primum mobile, whose diurnal rotation was
conferred upon it by a transcendental God, not part of the universe,
a motionless prime mover and first cause. The fixed stars were part
of this celestial sphere, all at the same fixed distance from the
immobile earth at the center of the sphere. Ptolemy had numbered
these at 1,022, grouped into 48 constellations. The planets were
each fixed to a transparent sphere.
In the first half of the 15th century Nicolaus Cusanus reissued the
ideas formulated in Antiquity by Democritus and Lucretius and
dropped the Aristotelean cosmos. He envisioned an infinite universe,
whose center was everywhere and circumference nowhere, with
countless rotating stars the Earth being one of them, of equal
importance. He also considered neither the rotation orbits were
circular, nor the movement was uniform.
In the second half of the 16th century, the theories of Copernicus
began diffusing through Europe. Copernicus conserved the idea of
planets fixed to solid spheres, but considered the apparent motion
of the stars to be an illusion caused by the rotation of the Earth
on its axis; he also preserved the notion of an immobile center, but
it was the Sun rather than the Earth. Copernicus also argued the
Earth was a planet orbiting the Sun once every year. However he
maintained the Ptolemaic hypothesis that the orbits of the planets
were composed of perfect circles - deferents and epicycles - and
that the stars were fixed on a stationary outer sphere.
Few astronomers of Bruno's time accepted Copernicus's heliocentric
model. Among those who did were the Germans Michael Maestlin
(1550-1631), Cristoph Rothmann, Johannes Kepler (1571-1630), the
Englishman Thomas Digges, author of A Perfit Description of the
Caelestial Orbes, and the Italian Galileo Galilei (1564-1642).
Bruno's cosmology was strongly influenced by Cusanus and Copernicus.
Bruno believed, as is now universally accepted, that the Earth
revolves and that the apparent diurnal rotation of the heavens is an
illusion caused by the rotation of the Earth around its axis. He
also saw no reason to believe that the stellar region was finite, or
that all stars were equidistant from a single center of the
In 1584, Bruno published two important philosophical dialogues, in
which he argued against the planetary spheres. (Two years later,
Rothmann did the same in 1586, as did Tycho Brahe in 1587.) Bruno's
infinite universe was filled with a substance -- a "pure air",
aether, or spiritus -- that offered no resistance to the heavenly
bodies which, in Bruno's view, rather than being fixed, moved under
their own impetus.
Most dramatically, he completely
abandoned the idea of a hierarchical universe. The Earth was just
one more heavenly body, as was the Sun. God had no particular
relation to one part of the infinite universe more than any other.
God, according to Bruno, was as present on Earth as in the Heavens,
an immanent God, the One subsuming in itself the multiplicity of
existence, rather than a remote heavenly deity.
Bruno also affirmed that the universe was homogeneous, made up
everywhere of the four elements (water, earth, fire, and air),
rather than having the stars be composed of a separate quintessence.
Essentially, the same physical laws would operate everywhere,
although the use of that term is anachronistic. Space and time were
both conceived as infinite. There was no room in his stable and
permanent universe for the Christian notions of divine Creation and
Under this model, the Sun was simply one more star, and the stars
all suns, each with its own planets. Bruno saw a solar system of a
sun/star with planets as the fundamental unit of the universe.
According to Bruno, infinite God necessarily created an infinite
universe, formed of an infinite number of solar systems, separated
by vast regions full of Aether, because empty space could not exist.
(Bruno did not arrive at the concept of a galaxy.) Comets were part
of a synodus ex mundis of stars, and not -- as other authors
sustained at the time -- ephemeral creations, divine instruments, or
heavenly messengers. Each comet was a world, a permanent celestial
body, formed of the four elements.
Bruno's cosmology is marked by infinitude, homogeneity, and
isotropy, with planetary systems distributed evenly throughout.
Matter follows an active animistic principle: it is intelligent and
discontinuous in structure, made up of discrete atoms. This animism
(and a corresponding disdain for mathematics as a means to
understanding) is the most dramatic respect in which Bruno's
cosmology differs from what today passes for a common-sense picture
of the universe.
During the later 16th century, and throughout the 17th century,
Bruno's ideas were held up for ridicule, debate, or inspiration.
Margaret Cavendish, for example, wrote an entire series of poems
against "atoms" and "infinite worlds" in Poems and Fancies in 1664.
His true, if partial, rehabilitation would have to wait for the
implications of Newtonian cosmology.
Bruno's overall contribution to the birth of modern science is still
controversial. Some scholars follow Frances Yates stressing the
importance of Bruno's ideas about the universe being infinite and
lacking structure as a crucial crosspoint between the old and the
new. Others disagree. Others yet see in Bruno's idea of multiple
worlds instantiating the infinite possibilities of a pristine,
indivisible One a forerunner of Everett's Many-worlds interpretation
of quantum mechanics.
"Firstly, I say that the theories on
the movement of the earth and on the immobility of the firmament
or sky are by me produced on a reasoned and sure basis, which
doesn’t undermine the authority of the Holy Scriptures […]. With
regard to the sun, I say that it doesn’t rise or set, nor do we
see it rise or set, because, if the earth rotates on his axis,
what do we mean by rising and setting ..."
- Giordano Bruno,
from the Vatican summary of
Bruno's trial ().
"I fought, and that's a lot. I thought I could win ... but
nature and luck curbed my endeavour. But it's already something
that I took up the struggle, because I see that victory is in
the hands of Fate. In me was what was possible and what no
future century will be able to deny to me: what a winner could
give from his own; that I did not fear death, that I did not
submit, my face firm, to anyone of my breed; that I preferred
courageous death to pavid life."
- Giordano Bruno,
"I cleave the heavens, and soar to the infinite. What others see
from afar, I leave far behind me."
- Giordano Bruno
The Pope & the Heretic, Michael
Vatican Secret Archives: Summary of
the trial against Giordano Bruno, Rome, 1597
Luigi Firpo, Il processo di Giordano
Site of Bruno's execution:
Alan Powers, Bristol Community
College, Campania Felix: Giordano Bruno’s Candelaio and Naples
accessed 27 May 2007
Hans-Volkmar Findeisen: „Gegenpapst
und Designer des Darwinismus“ – Wer kennt heute eigentlich noch
Ernst Haeckel? (in German) accessed 27 May 2007
Sheila Rabin at the Stanford
Encyclopedia of Philosophy: "Thus, in 1600 there was no official
Catholic position on the Copernican system, and it was certainly
not a heresy. When Giordano Bruno (1548-1600) was burned at the
stake as a heretic, it had nothing to do with his writings in
support of Copernican cosmology." Nicolaus Copernicus in the
Stanford Encyclopedia of Philosophy (online, accessed 19
Similarly, the Catholic Encyclopedia
(1908) asserts, "Bruno was not condemned for his defense of the
Copernican system of astronomy, nor for his doctrine of the
plurality of inhabited worlds, but for his theological errors,
among which were the following: that Christ was not God but
merely an unusually skilful magician, that the Holy Ghost is the
soul of the world, that the Devil will be saved, etc." Turner,
William. "Giordano Bruno.” 1908. Catholic Encyclopedia accessed
2 Jan. 2007.
Vatican Secret Archives accessed 3
 Max Tegmark, Parallel Universes,
Bruno, GiordanoThe Acentric
Labyrinth. Giordano Bruno's Prelude to Contemporary Cosmology,
Ramon G. Mendoza PhD, 1995, ISBN 1-85230-640-8
Cause, Principle and Unity : And
Essays on Magic by Giordano Bruno, ISBN 0-521-59658-0
The Cabala of Pegasus by Giordano
Bruno, ISBN 0-300-09217-2
"Writings of Giordano Bruno"
The Pope & the Heretic, Michael
White, 2002, ISBN 0-06-018626-7.
Giordano Bruno, J. Lewis McIntyre.
Giordano Bruno and Renaissance
Science, Hilary Gatti, 2002, ISBN 0-8014-8785-4
Giordano Bruno: His Life and
Thought, With Annotated Translation of His Work -On the Infinite
Universe and Worlds,Dorethea Singer,1950.
Giordano Bruno: The Forgotten
Philosopher, John Kessler.
Giordano Bruno, Paul Oskar
Kristeller, Collier's Encyclopedia, Vol 4, 1987 ed., pg. 634
Giordano Bruno and the Hermetic
Tradition, Frances Yates, ISBN 0-226-95007-7
Eros and Magic in the Renaissance,
Ioan P. Couliano, ISBN 0-226-12315-4.
Il processo di Giordano Bruno, Luigi
Giordano Bruno,Il primo libro della
Clavis Magna, ovvero, Il trattato sull'intelligenza artificiale,
a cura di Claudio D'Antonio, Di Renzo Editore.
Giordano Bruno,Il secondo libro
della Clavis Magna, ovvero, Il Sigillo dei Sigilli, a cura di
Claudio D'Antonio, Di Renzo Editore.
Giordano Bruno, Il terzo libro della
Clavis Magna, ovvero, La logica per immagini, a cura di Claudio
D'Antonio, Di Renzo Editore
Giordano Bruno, Il quarto libro
della Clavis Magna, ovvero, L'arte di inventare con Trenta
Statue, a cura di Claudio D'Antonio, Di Renzo Editore
Giordano Bruno L'incantesimo di
Circe, a cura di Claudio D'Antonio, Di Renzo Editore
Giordano Bruno, De Umbris Idearum, a
cura di Claudio D'Antonio, Di Renzo Editore
Guido Del Giudice, La coincidenza
degli opposti, Di Renzo Editore, ISBN 8883231104 , 2005
Giordano Bruno, Due Orazioni: Oratio
Valedictoria - Oratio Consolatoria, a cura di Guido del Giudice,
Di Renzo Editore, 2007
The 20-km diameter crater Giordano
Bruno, named in Bruno's honor, is located on the moon at
103°east lunar longitude, 36° north lunar latitude. It is
believed to have been created by a meteorite impact in 1178,
witnessed by five English monks as related in Carl Sagan's
In 1926 the Theosophical
Broadcasting Station Pty Ltd, owned by interests associated with
the local branch of Theosophical Society Adyar, was granted a
radio broadcasting license in Sydney, Australia. The station's
call sign, "2GB" was chosen to honour the Italian philosopher
who was much admired by Theosophists. Although the ownership of
the station subsequently passed to strictly commercial interests
the call sign is retained.