Islam did not oppose new cultures and the knowledge that they brought with them. Arabic, however, remained the official language. And the Muslim faith spread through the territories that the Empire conquered. There was, however, much religious tolerance. The Empire allowed non-Muslims to participate in high-ranking positions and other sociopolitical roles. For these reasons, many cultures and many people were able to mix without difficulty. Commerce was booming. Economic systems were evolving. Knowledge was being shared on a daily basis. And as the Empire expanded and Arabic gained popularity, the Islamic nation flourished during a time where the whole world was struggling.