Budge, welcome.
I see you've posted in the Legacy Forum, but Black Prince is not an old timey legacy variety as most of the others being discussed here. But no problem/
And now to your question.
First, none of the so called blacks are really purple. The only two varieties that I know of that have a tint of purple are Noire des Cosebeauf and Purple Calabash, and IMO growing them once is enough.
Black prince was first listed in the 1995 SSE Yearbook and most folks got their seed from Nichols Nursery in Oregon and Rose Nichols McGee got it from someone else in OR in the early 90's.
It's one of well over 100 so called black varieties known. I've grown it, but don't take my word for taste, etc., b'c I have to admit that with just a few exceptions I'm not a great lover of blacks.
BTW, the word purple started being used in the late 1800's to describe a PINK variety, so we have Aunt Ginny's Purple, Eva Purple Ball and on and on......all PINK.
So grow it and see how you like it, knowing that if it's blacks you're interested in that there about 100 more different varieties to chose from.
