Richard Oakes was a leading Native American activist, best known for leading the 'Occupation of Alcatraz'.

A Google Doodle has marked what would have been his 75th birthday.

Oakes was born in New York on May 22, 1942. He was a member of the Mohawk tribe, which originated in the northeastern United States and southeastern Canada.

He spent much of his childhood fishing and planting crops, but this way of life was destroyed by the construction of the St Lawrence Seaway, a vast system of locks, canals and channels. Oakes found work as a docker and a steelworker.

In 1968 he married and had a son, but he divorced shortly after and moved to San Francisco, enrolling at San Francisco University.

Dissatisfied with the curriculum, Oakes played an integral role in developing the first Native American studies department in the nation. He developed the curriculum and encouraged other Native American people to enrol at the university.

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Oakes became a champion of social justice for Native Americans, and in 1969 he led a series of protests, including leading a group of more than 80 people to occupy the disued Alcatraz Island for almost 19 months.

We invite the United States to acknowledge the justice of our claim Richard Oakes

According to the protesters, abandoned or out-of-use federal land could be returned to the Native people under the Treaty of Fort Laramie.

Since Alcatraz penitentiary was closed, and the island had been declared a surplus federal property, many activists felt the island qualified for reclamation.

The protesters aimed to set up a community, complete with a university, museum and cultural centre, but they also wanted the government to acknowledge the rights to Native Americans to claim the out-of-use federal land as their own.

"We invite the United States to acknowledge the justice of our claim. The choice now lies with the leaders of the American government - to use violence upon us as before to remove us from our Great Spirit's land, or to institute a real change in its dealing with the American Indian", said Oakes in a message to the San Francisco office of the Department of the Interior.

"We do not fear your threat to charge us with crimes on our land. We and all other oppressed peoples would welcome spectacle of proof before the world of your title by genocide. Nevertheless, we seek peace."

In June 1971, the government removed the remaining 15 occupants from the island. However, the occupation started a national dialogue about the plight of Native Americans, and soon after President Nixon spoke in support of self-determination.

Oakes continued with his activism, and in 1971 he aided the Pit River Tribe to recover nearly three million acres of land that had been seized by Pacific Gas and Electric. Oakes also envisioned a 'mobile university' aimed at creating opportunities to Native Americans, but the project didn't materialise.

As a result of his activism, Oakes endured tear gas and brief stints in jail. He was shot and killed after an argument with a Californian YMCA leader in 1972.

"Here's to Richard Oakes, for his unwavering dedication to his community and social justice," wrote Google.