The Persian Empire was one of the first empires to practice religious and cultural tolerance to the people they conquered. Despite their reputation as conquerors, life under the Persian Empire was typically characterized by peaceful trading and economic prosperity.
When two species compete for the same limiting resource the reduction of the niche overlap may lead to evolutionary changes in both species.
Alternatively the competitively dominant species does not change and is maybe even able to expand its niche, and thus reduces niche space available for the other species.
