Even though Major League Baseball is celebrating Jackie Robinson Day on Sunday, baseball historians and authors have taken to Twitter to remind the masses that Jackie Robinson breaking MLB’s color barrier with the Brooklyn Dodgers in 1947 wasn’t welcome by everyone.

The historians also wanted to remind baseball fans that many of the issues Robinson mentioned as a player and as an activist after he retired, such as police brutality, civil rights and diversity on team rosters and in management are still relevant in today’s political and social discourse.

Robinson himself wrote a series of columns and editorials for black newspapers such as the Chicago Defender and the New York Amsterdam News, blasting America for being slow to address racism and poverty.

In Robinson’s memoir, “I Never Had It Made,” he discussed his issues with the National Anthem:

“There I was the black grandson of a slave, the son of a black sharecropper, part of a historic occasion, a symbolic hero to my people. The air was sparkling. The sunlight was warm. The band struck up the national anthem. The flag billowed in the wind. It should have been a glorious moment for me as the stirring words of the national anthem poured from the stands. Perhaps it was, but then again perhaps the anthem could be called the theme song for a drama called XXThe Noble Experiment. Today as I look back on that opening game of my first world series, I must tell you that it was Mr. Rickey’s drama and that I was only a principal actor. As I write this twenty years later, I cannot stand and sing the anthem. I cannot salute the flag; I know that I am a black man in a white world. In 1972, in 1947, at my birth in 1919, I know that I never had it made.”