Dive into a timeline covering the subjects of Clear and Present Danger. The timeline will expand as we travel through the history of free speech.

Free speech history

854-c.925: al-Rāzī

854-c.925: al-Rāzī

al-Rāzī examining a sick boy (Color print after Hossein Behzad)


The Persian thinker Abū Bakr Muhammad ibn Zakariyyā al-Rāzī is better known as ‘Rhazes’ to most Westeners. His almost 200 books span everything from medicine and chemistry to logic and philosophy. Supposedly, all the reading and writing makes him go blind and his hand paralysed. His greatest achievements include the discovery of alcohol as well as groundbreaking works on measles and smallpox.


As a religious freethinker, his criticism of revelation in general and of the Qurʾān in particular leads to multiple accusations of heresy. For al-Rāzī:


“Reason is the ultimate authority, which should govern and not be governed; should control and not be controlled, should lead and not be led.” – al-Rāzī


c.870-951: al-Farabi

c.870-951: al-Farabi

al-Farabi’s portrait on a Kazakh banknote (Public Domain)


Abu Nasr al-Farabi excels in two areas. As a philosopher and logician he is known as “the second master”, only surpassed by Aristotle. As a musicologist, his Kitâb al-musiqâ al-kabîr or Great Book of Music is the most influential work on music from the Islamic Middle Ages.

980-1037: Ibn Sina (Avicenna)

980-1037: Ibn Sina (Avicenna)

Miniature of unknown origin (Wiki Commons)


No figure from the Islamic Golden Age towers above Ibn Sina. To most Westeners he is better known as Avicenna. His achievements in philosophy and medicine not only shape Islamic but also European thinking for centuries. When works like his Canon of Medicine are translated into Latin, they become core curriculum in most European universities.

1058-1111: al-Ghazali

In The Incoherence of the Philosophers, the influential philosopher and theologian al-Ghazali launches an attack on Aristotilean thinkers like Ibn Sina and al-Farabi. Al-Ghazali is often depicted as a strict opponent to reason, but modern scholars think he has been misinterpreted.


Al-Ghazali identifies three propositions so problematic that advocates should be executed without chance to repent:

1) That the world was not created

2) That God is not omniscient

3) That the rewards and punishments in the next life are only spiritual in character

1258: The Siege of Baghdad

1258: The Siege of Baghdad

Illustration, c. 1430, from Bibliothèque nationale de France (Public Domain)


In the 13th century, the Mongols burst out of the Asian Steppe to conquer everything from China to Russia.


In the winter of 1258, the Mongols lay siege to the ʿAbbāsid capital of Baghdad ushering the fall of the ʿAbbāsid Caliphate and putting a stop to the Islamic Golden Age. According to survivors, the river Tigris runs black with the ink of destroyed books and red from the blood of philosophers and scientists.

The European Middle Ages

Episode VI: The Not so Dark Ages

Episode VI: The Not so Dark Ages

In episode VI, we get Medieval! Find out why the Middle Ages were as much a period of inquisition and persecution as reason and inquiry.


Why was the famous medieval intellectual Pierre Abelard castrated, forced to burn his works, and condemned to silence by the church? How did the combination of Aristotelian philosophy and the development of universities institutionalize reason and science? What are the parallels between clashes over academic freedom in the 13th and 21st centuries? All this and much more in “Clear and Present Danger” – episode VI!

800: Charlemagne

800: Charlemagne

Illumination from 14th century manuscript showing the coronation of Charlemagne (Public Domain)


On new years eve 800, Charlemagne is named Holy Roman Emperor by Pope Leo III. With his court in Aachen, Charlemagne kicks off a number of reforms, reviving the Latin language and rescuing Ancient manuscripts from oblivion.


Blasphemy is a capital crime, heretics like the adoptionists are persecuted and heathens are forced to convert by the sword.

The High Middle Ages

c. 1100: The 12th century Renaissance

c. 1100: The 12th century Renaissance

Winchester Cathedral from 1079 is one of the first – and largest – Gothic cathedrals in Europe (Public Domain)


Around the turn of the millennium, new farming techniques are invented. Modern historians believe the weather is getting warmer and more stable too.


The European population virtually explodes, either doubling or trebling in size between 1000 and 1300. New cities sprout up and the continent enters a period of social, intellectual and cultural transformation later known as the 12th century Renaissance.

1079-1142: Pierre Abelard

1079-1142: Pierre Abelard

14th century miniature of Abelard and Héloïse (Public Domain)


The philosopher, theologian and poet Pierre Abelard is equally famous for using reason in matters of faith and his tragic love affair with Héloïse. The affair is brutally ended when Abelard is castrated by Héloïse’s uncle, Fulbert.


Two trials deem his theological works on the Trinity too controversial. The works are condemned and burned.


“By doubting we come to questioning, and by questioning we perceive the truth” – Pierre Abelard (1079 – 1142)

c. 1200: Birth of the European University

c. 1200: Birth of the European University

16th century miniature of a congregation of doctors at the University of Paris (Public Domain)


Europe’s first universities evolve in Paris and Bologna around 1200. Masters and students form artisan guilds known as universitas magistrorum et scholarium. Within a few years, England’s first universities evolve in Oxford and Cambridge. By 1300, 18 universities have emerged across the continent. By 1500, the number is 70.

1200-1400: Censorship at the first universities

With the birth of the university in the 13th century, the masters of theology assume the role of heresy police. There are about 50 known cases of academically related trials in the thirteenth and fourteenth centuries.


The first offender is Master Amalric of Bène. Around 1206, he is found guilty of false teaching for advocating pantheism. Four years later, he is excommunicated and his followers are burned outside the gates of Paris.


However, the majority of such cases convict books – not persons. The offender is free to continue his career if he recants and burns the problematic work.

1225–1274: Thomas Aquinas

1225–1274: Thomas Aquinas

Thomas Aquinas sitting between Plato (right) and Aristotle (left) in Benozzo Gozzoli’s Triumph of St. Thomas Aquinas (1470-1475) (Public Domain)


The Dominican friar Thomas Aquinas is arguably the most influential thinker of Medieval Europe.


Following the footsteps of his old scholastic master, Albert the Great, he finds a feasible synthesis between revelation and Aristotilean philosophy. His achievements include the Quinque viæ or five proofs for the existence of God. Most of the proofs are build on Aristotilean and Platonic ideas.

1277: The Double Condemnations of 1277

1277: The Double Condemnations of 1277

Bishop Tempier wagging his finger at problematic propositions (Public Domain)


In March 1277, the Parisian bishop Étienne Tempier compiles a list of 219 forbidden propositions, including the notion that “happiness is found in this life, and not in another”. The Archbishop of Canterbury, Robert Kilwardby, accedes to the double condemnation.


Most of the 219 articles come from Aristotle or aristotelians like Thomas Aquinas, Siger of Brabant and the Islamic scholars Ibn Rushd and Ibn Sina.

The Late Middle Ages

C. 1287–1347: William of Ockham

C. 1287–1347: William of Ockham

Glass mosaic in Surrey


William of Ockham is probably best known for his razor: The problem-solving principle of choosing the solution based on fewest assumptions. His achievements also include significant contributions to the fields of logic, physics, philosophy and theology.


In 1339 and 1340, his ideas are banned in the Parisian arts faculty in two statutes.

1299-1369: Nicholas of Autrecourt

The philosopher Nicholas of Autrecourt is known as the ‘Medieval Hume’. In 1346, he is found guilty of false teaching. He is ordered to burn his works and deprived of his title as master of arts.

Episode VIII: The Hounds of God

Episode VIII: The Hounds of God

From the High Middle Ages, Europe developed into a “persecuting society,” obsessed with stamping out the “cancer” of heresy. But questions about how this was accomplished — and the consequences of these developments — abound:

  • Why did popes and secular rulers shift from persuasion to persecution of heretics?
  • Why was human choice in matters of religious belief considered a mortal threat to Christendom itself?
  • Why did bookish inquisitors armed with legal procedure, interrogation manuals, data and archives succeed where bloody crusades and mass slaughter failed?
  • How did the “machinery of persecution” developed in the Late Middle Ages affect other minority groups such as Jews?
  • Are inquisitions a thing of a past and dark hyper-religious age, or a timeless instrument with appeal to the “righteous mind” whether secular or religious?
  • What are the similarities between medieval laws against heresy and modern laws against hate speech?

We try to answer these questions — and more — in episode 8 of Clear and Present Danger: The Hounds of God.

1022-1052: 11th century persecutions

In the 11th century, the attitude towards heretics slowly begins to turn from persuation to persecution.


In 1022, King Robert II of France burns 14 prominent clerics and nobles to death in Orleans.


In 1028, a group of ascetics – now thought to have been Neoplatonists – are accussed of being Manicheans. They are burned to death in Monforte in Italy.


In 1052, the Holy Roman Emperor Henry III suspects a group of being Manicheans and order them to kill a chicken to prove their innocense. When they refuse, they are hanged.

1184-1230: The Medieval Inquisition

The Medieval Inquisition covers a series of inquisitions from the Episcopal Inquisition of 1184 to the Papal Inquisition of the 1230s.


Pope Lucius III kicks off the first, Episcopal Inquisition in 1184 as a response to two growing movements: the Cathars and the Waldensians, who are excommunicated and branded as heretics. In a papal bull, he instructs bishops to comb their juristictions for heretics twice a year


His successor, Innocent III, steps up the Inquisition in 1199 when he makes heresy a crime akin to high treason. In 1208, he calls for a crusade on the Cathars and between 10,000 and 15,000 are massacred in the city of Beziers.


In 1231, Pope Gregory IX orders Dominicans in the German city of Regensburg to “seek out diligently those who are heretics or are infamed of heresy”. From 1231, heretics are burned to death at the stake.

1415: The execution of Jan Hus

1415: The execution of Jan Hus


The Jena codex, c. 1500, showing the execution of Hus (Public Domain)


1415 is a watershed moment in the history of free speech. On July 6 the Czech theologian Jan Hus is burned to death in Jena. He is the first person in 200 years to be executed for heresy.


The execution is a sign of times to come. Heretics are persucted in greater numbers and with harder measuers in the 15th and 16th centuries.

1478: The Spanish Inquisition

1478: The Spanish Inquisition

Illustration from late 18th century edition of John Foxe’s Book of Martyrs (Public Domain)


The Spanish Inquisition was launched in 1478 by the two Catholic monarchs Ferdinand II of Aragorn and Isabella I of Castile to purify the two kingdoms of heresy. It was replacing the so-called Medieval Inquisitions from the 12th and 13th centuries. The Spanish Inquisition was not abolished until 1834.


According to some estimates, 150,000 were persecuted of which between 3,000 and 5,000 were executed.