Complex sentence: Its ruling house had the surname "Mi" (芈), and clan name "Xiong" (熊), and originally was of the noble rank of "Zi", roughly comparable to a viscount.
Split into simpler sentences: Its ruling house had the surname "Mi" (芈), and clan name "Xiong" (熊). Originally Chu's rulers were of the noble rank of "Zi" (子), roughly comparable to a viscount.