A sickening terrorist attack this morning at the Paris offices of Charlie Hebdo—a satirical weekly French magazine—has left 12 people dead and 10 others injured. In what the Associated Press has said is the most deadly attack in France in over 20 years, three masked gunmen carrying automatic weapons stormed the newsroom, shooting and killing 10 staff members and two police officers while also wounding 10 others. They then escaped in a van and are now being pursued across the city by all levels of law enforcement.

Obviously, this is a terrible tragedy and a horrifying affront to the freedom of speech. But with their left-wing politics and renown refusal to bend to political correctness, Charlie Hebdo in particular is no stranger to upsetting people and being threatened with violence. Here are some essential facts you need to know about the magazine:

  • They have many enemies in the Muslim world. In 2011, they put a cartoon depiction of the Prophet Muhammad on the cover of the magazine, which caused their office to be firebombed and their website hacked.
  • In response to the attacks on U.S. embassies around the world (which themselves were a response to an anti-Islamic film), the magazine again published multiple cartoons of Muhammad in 2012. Some of them were nude caricatures. Riot police had to form a circle around the building to prevent any attacks on the offices.
  • The weekly magazine first ran from 1969 to 1981, but then it was forced to fold before coming back in 1992.
  • The magazine was initially banned by the Minister of the Interior after running an article mocking the death of former president Charles de Gaulle in 1970.
  • The name “Charlie Hebdo” traces back to Charlie Brown and the Peanuts cartoon series, and was created to get around the aforementioned ban.
  • In 2006, a cover that depicted a weeping Muhammad with a caption that translated as “it's hard being loved by jerks” caused them to be sued by The Grand Mosque, the Muslim World League and the Union of French Islamic Organisations. Charlie Hebdo ultimately prevailed.