Islam was first introduced to China in 650 CE through the delegation sent by Caliph Uthman ibn Affan that was led by Saad ibn Abi Waqqas, one of Prophet Muhammad's companions. Saad invited the Chinese emperor to embrace Islam, and while he did not convert, he respected Islam and allowed the establishment of the first mosque in China. Over subsequent centuries, trade and religious interactions increased Muslim presence in China, though they faced some oppression from certain dynasties through the 19th century. Currently it is estimated there are over 200 million Muslims in China, representing the largest Muslim population outside of Islamic countries.