What two empires? please specify
The country in question would be Singapore
Both were black nationalist groups but the difference is that the Black Panther Party (BPP) were a more right-winged extremist group compared to the National Urban League (NUL) when it came to the two political/social activist parties. Basically the BPP were willing to break the law to achieve their demands, while the NUL did it via the system with more progressive tactics. Or, less violent at the least.
B separatists wants to break away from the Church of England believing it to not be reformable.
Your answer would be a it was so rare because a symbol of great status and wealth hope this helped have a great day