This question was brought on by watching the Witcher and Beauty and the Beast. In both, black people can be seen to occupy meaningful positions at court, as an adviser or similar. As such, it might already have an answer I did not find yet. Now, diversity in film is desirable and easily explained away with the fact that these are fictional settings. But I still wonder how the fiction measures up to the history that inspired it.
Trade was established with the Orient and the Islamic World was influential well after the middle ages. There is no logistical reason you wouldn't have Africans at court. But the past is a pretty racist country, and as I understand it by 1800 "black" was synonymous with "slave", but maybe before the triangle trade, there is some chance?
I promise this question is asked in good faith and out of curiosity. I am asking because I did not find stuff, and if I did, it would probably be by people with an agenda. I am sorry I couldn't be more precise with the time frame, the fact that these are fictional settings means there isn't a clear year to compare them to. If there is an answer somewhere else, please excuse the question and simply point me to it.
There is always more to be said, but this is a reoccurring question that is usually tied to a specific book, film or TV show, which would likely explain your difficulty in finding previous questions about it. Nonetheless, the answer is certainly yes, but it's a basic answer that needs to be contextualized with the difficulty of recreating these lives from the archives. I've spoken about this in particular in this question. A recent question on the topic that I answered concerned Lieutenant Mattias in Frozen II (since you mentioned Beauty and the Beast) who is portrayed as being of African ancestry. I answered that question here.