This is one of the displays at the National Civil Rights Museum which relates to the sanitation strike which took place in Memphis. Black workers were paid less than their white colleagues, and treated more harshly with fewer opportunities, which led to a strike and march where they had posters with the “I am a Man” slogan on them.
It was this strike that what the reason that Martin Luther King came to Memphis, and was sadly assassinated whilst staying in Room 306 at the Lorraine Motel.
The above article was published by a local newspaper at the time, and there was some surprise amongst the ‘whites’ that the issue had escalated. But paternalism and the concept of inequality were always the main issue that underpinned everything.
The phrase, which is perhaps better known more recently in some quarters today with Will in the Inbetweeners using the phrase (in an unrelated manner) when trying to buy alcohol in an off-licence. The phrase though dates back to the late eighteenth century, when a tract was published with the title “Am I Not a Man and Brother?” and it became used in the anti-slavery movement. It’s a very powerful line.