Complex sentence: He was not of Han Chinese origin, and some historians believe he may have come from a Slavic background, although others assert it is much more probable that he was of Tibetan, Magyar, Hun or Persian ancestry.
Split into simpler sentences: He was not of Chinese origin, and some historians believe he may have come from a Slavic background. Although others assert it is much more probable that he was of Tibetan, Magyar, Hun or Persian ancestry.