Near the end of his life, Steve Biko wasn’t permitted to speak to more than one person at a time, but that didn’t stop him from spreading the message of equality for all.

Biko was an anti-apartheid activist in the 1960s and ’70s, when the system of racial segregation and discrimination was at its height in South Africa. To highlight Biko’s contribution to getting the system abolished, Google published a doodle Sunday to honor Biko on what would have been his 70th birthday.

Famous for the slogan “black is beautiful,” Biko founded the Black Consciousness Movement, which battled apartheid and encouraged black people to take pride in their racial identities. His political activities led to his expulsion from medical school in 1972.

A year later, he was banned by South Africa’s apartheid government, meaning he was forbidden from speaking to more than one person at a time, speaking in public, or writing or speaking to the media. It was also illegal to quote him, either from a speech or simple conversation.

Despite Biko’s repression by the government, he continued organizing protests, including 1976’s Soweto Uprising, a student protest that led to deadly confrontations with the police. He died a year later in police custody at the age of 30.