NEW YORK • Inter-racial waters in the United States were tested by cartoonist Charles M. Schulz when Franklin said: "Is this your beach ball?" The black character was speaking to white kid Charlie Brown as the latter stared glumly out to sea.
The coming together occurred in comic strip Peanuts on July 31, 1968.
Franklin's initial three-strip arc unfolded quietly and gently, with the boys building a sandcastle.
He stayed quiet and gentle, taking his place in the Peanuts gang as a steady but low-key presence over the next three decades - sometimes to the chagrin of African-Americans who found him to be anodyne at best and a token at worst.
In a 1992 Saturday Night Live routine, Chris Rock complained, comically but pointedly, that Schulz had deprived Franklin of the kind of signature traits he had assigned the other Peanuts kids.
"Linus got the blanket... Schroeder plays the piano, Peppermint Patty's a lesbian," Rock said. "Everybody got their thing except Franklin. Give him something."
Yet Franklin's careful roll-out and nice-guy equanimity were very much by design, as 50 Years Of Franklin, a new exhibition at the Charles M. Schulz Museum in Santa Rosa, California, reveals.
The event opened over the weekend in conjunction with the observance of Martin Luther King Jr's birthday yesterday.
The latter's assassination in 1968 played a direct role in Franklin's creation. A Californian named Ms Harriet Glickman wrote to Schulz, introducing herself as "the mother of three children and a deeply concerned and active citizen".
In her grief, she had been pondering "the areas of the mass media which are of tremendous importance in shaping the unconscious attitudes of our kids".
She proposed "the introduction" of black children into the group of Schulz characters.
Peanuts was then at the peak of its popularity, with a devoted daily readership nearing 100 million.
Schulz wrote back to tell her he could not fulfil her request. He and his fellow white cartoonists were "afraid that it would look like we were patronising" blacks. She asked if she could share his letter with black acquaintances.
Ms Glickman wasted little time in enlisting her friend Kenneth C. Kelly, a black father of two, who told Schulz to get over his anxiety.
He suggested that Schulz begin with a black character who "would quietly... set the stage for a principal character at a later date".
This would serve the dual purpose of not burdening Schulz and Peanuts with the duty of making a major social statement and presenting friendship between black and white children as utterly normal.
But in the context of the late 1960s, Franklin's debut was indeed a statement. Inevitably, a few newspaper editors in the South made noises of protest, but by and large, the reaction was positive, particularly among black readers.
Morrie Turner, whose Wee Pals, introduced in 1965, was the first widely syndicated strip by an African-American cartoonist, told Schulz he found the "treatment of the character excellent".
In the long run, Franklin ended up existing in a space somewhere between an extra and a principal, most reliably serving as the academically proficient straight man to Peppermint Patty's perpetually D-minus-pulling goofball.
Schulz, who died in 2000, was generally wise to stay within his lane. He correctly intuited that he could go only so far in portraying a black child's experience.
Fifty years after Franklin recovered Charlie Brown's beach ball, Americans are still living through times when representational firsts are newsworthy - the first kiss between Asian and African-American characters in a Star Wars film (Rose and Finn in The Last Jedi, 2017), the first Marvel Studios movie headlined by a black superhero (next month's Black Panther).
Franklin might not have been the most fascinating fellow ever to populate the comics universe, but as his story shows, a first like him is needed to advance the march of representation.
When Ms Glickman, now 91, was asked if she was disappointed by Franklin's relative blandness, she laughed at the very thought.
"Never. Are you kidding me?" she said. "I was so pleased with Charles Schulz. He did what he could do at the time."