Today is Martin Luther King Day, the only American holiday that honors a Black person. Most people know King was an African-American, but how many people know he was part Irish? That's right, the most famous Black person in U.S. history actually had some European ancestry. According to this page from Stanford University, King's grandfather, James Albert King, was Irish-African (that probably means he was half Irish and half Black) which would make Martin Luther King one-eighth Irish. And in the past, I read somewhere that he was 1/8 Irish. So it's probably true.
Some people might be shocked to know he was part Irish, but it's really nothing surprising. Many African-Americans today have distant non-Black ancestors (usually American Indian or European). This likely explains why some African-Americans are more light-skinned than others (and these particular Black people aren't known to be multiracial). Some examples I can think of are:
These people are all generally assumed to be "full" Black, but they are rather light-skinned. Colin Powell certainly looks like he's more White than Black (in my opinion). Before Michael Jackson surgically became White, he had about the same light-brown skin color as Will Smith. And I've never heard anything about Beyoncé being multiracial.
It is possible that these people have more European ancestry than Martin Luther King did (since King was known to be part Irish, and he was darker than most of them). I can understand why he's considered to be full Black instead of mixed-race (1/8 Irish is very small), but I wish more people would know that "full Black" doesn't necessarily mean "100% African heritage." In fact, "100% American heritage" would be more accurate, keeping in mind that "American" is not a race or an ethnicity, it's an identity that transcends both of those.