Short answers, pulled from the story.
Diagoras of Melos was sentenced to death for making fun of the Eleusinian Mysteries and was forced to flee Athens to escape execution. Socrates also faced a death sentence in 423 BCE for the crime of not believing in the gods of the state.
Matthias Knutzen published three writings in 1674 that openly denied the existence of God. This event marked the first known explicit atheist in the modern era before the explosion of atheistic thought in the 18th century.
China has the highest percentage of convinced atheists at 47%, followed by Japan at 31% and the Czech Republic at 30%. A 2010 survey published in Encyclopædia Britannica found that atheists made up only 2.0% of the world's population.
A 2016 study found that self-identified atheists scored 18.7% higher than theists on the cognitive reflection test. This suggests that disbelief in religion results from the application of higher-level analytical reasoning to the assessment of religious claims.
The Roman Empire executed Christians for rejecting the Imperial cult when Christianity became the state religion under Theodosius I in 381 CE. This event made heresy a punishable crime and turned the label of atheism against its own citizens.
Melbourne hosted the first Global Atheist Convention in 2010, which drew over 2,000 delegates. The event sold out more than five weeks prior to its date and signaled a new era of organized atheistic activism.