Atheism is the rejection of a belief in God. Although there had been traditions of atheism in the classical Greek world, there was no such tradition in medieval Europe. Attempts by medieval writers to “prove” the existence of God were not counters against atheism but rather intellectual discussions among Christians.

It may seem remarkable now but the concept of atheism simply did not exist for medieval Europeans.

When the word atheism began to appear in European languages in the sixteenth century, it was rarely meant as we use it today but a means to attack those with whom one radically disagreed religiously. They rejected the correct path to God to an outrageous degree rather than coolly rejecting God as a concept.

During the seventeenth century, a movement named Deism began to deny the aspects of personal revelation in traditional Christianity, instead focusing on knowing God through reason and observation of nature.

What this meant was that there was no god watching over you. God was a presence in the Universe, creating harmony and intelligence. That also suggested that no one got judged at the end of time.



The Dutch Jewish philosopher Spinoza who lived in the seventeenth century has been described as the first “semi-atheist”. He did not quite deny the existence of God, but stated that God was not in any way conscious or at all involved in human lives, but was rather just the nature of existence itself. This was a radical break from the watchful, judging god of the Judeo-Christian tradition.

The first recorded person to outright reject the existence of God was a Polish nobleman named Kazimierz Łyszczyński in 1674. He stated that “man is a creator of God, and God is a concept and creation of a Man”. He was tortured to death for writing these words.

Lastly, when a French priest named Jean Meslier died in 1729, an unpublished book of his was discovered in his house, in which he denied the existence of any god and refuted all religions, in a way we might recognise today as atheist. Voltaire edited and published the work many years after Meslier’s death. It was widely read, the first publicly available argument against the existence of God, or any god.



During the 18th century, our modern understanding of the word “atheist” as someone who rejected a belief in God – beyond the Deist discussion of the nature and identity of God – became more common. Atheism remained a controversial – and potentially socially disastrous – position to hold publicly until the 20th century. Although the French Revolution had sought to replace Christianity as the state religion, it was not until the rise of Communism that states first embraced atheism instead of a state religion.

We include explanations of the development of Deism and Atheism in our upcoming book, A Quick History of Christianity. Sign up to our mailing list now to receive a free copy before publication this summer, or to hear about our other exciting new books. Or alternatively, leave a comment below. Which other writer or thinker do you think played a role in the development of what we call atheism today?