Why was there a rivalry between Diddy and Tupac?

There was a rivalry between Diddy and Tupac because Diddy was Boss of the east coast label Bad Boy that notorious B.I.G was a part of. Diddy was caught in the midst of the feud between Tupac Shakur and Notorious B.I.G.

In the 1990’s, especially from 1994 – 1997 there was a great rivalry between the east coast and the west coast artists and fans in the United States. The focal point of this feud was between B.I.G (and his New York based label, Bad Boy Records and Diddy was Boss) and Tupac Shakur (and his Los Angeles based label, Death Row Records).