June 2 marks Gilbert Baker’s birthday, and although you might not know his name, you’re almost certainly familiar with his most enduring contribution: the rainbow flag that’s become synonymous with the LGBT rights movement.

Baker—who is being honored with a Google Doodle today—was born in Chanute, Kansas in 1951. After a stint in the Army, he settled in San Francisco, which had seen itself transform into a community that both welcomed and endorsed civil rights for women and other under-represented segments of society. Because Baker had taught himself to sew, friends would often ask if he could create something that could be identified with the rising number of men who were coming out of the closet in San Francisco and elsewhere. For protests and marches, community members wanted a symbol to help communicate the idea of a unified stand.

Some earlier banners had used a pink triangle, a reclaiming of the same symbol used by Nazis to identify gay men in concentration camps during World War II. In 1978, prominent gay rights advocate Harvey Milk asked Baker for an original emblem. With the help of volunteers, Baker filled several trash cans with dye, dipped fabric, and emerged with a rainbow flag with eight stripes.

Each color had a distinct meaning: Orange indicated healing; yellow meant sunlight; violet meant spirit. Following Milk’s assassination that same year, demand for the flag grew so intense that Baker, who couldn’t quite keep up with production, reduced the number of colored stripes to six. (He would later partner with a manufacturing company to make sure the flags were readily available.)

Although Baker could refer to its creation with some levity—he once called himself the “gay Betsy Ross”—it was clear that he was touched by how deeply the flag had embedded itself into the fabric of civil rights. “What the rainbow has given our people is a thing that connects us,” he once said. “I can go to another country, and if I see a rainbow flag, I feel like that’s someone who is a kindred spirit or [that it’s] a safe place to go. It’s sort of a language, and it’s also proclaiming power.”

The flag went on to become ubiquitous, with Baker—who died in March 2017 at age 65—credited with creating an iconic visual that could communicate the demand for tolerance in an instant. In 2003, he helped with the creation of the largest LGBT flag ever, one that covered more than a mile of Key West. When gay marriage was legalized by the Supreme Court in 2015, more than 26 million Facebook users changed their profile image to include the flag’s design. And in 2015, the Museum of Modern Art inducted it into its design collection.