Complex sentence: In 621, the founder of the Tang dynasty was victorious over Wang Shichong and Dou Jiande, the latter of which was the father of Xianniang, another female warrior who became Mulan's blood sister in the "Sui Tang Romance".
Split into simpler sentences: In 621, the Tang's founder was victorious over Wang Shichong and Dou Jiande. The latter was the father of Xianniang, another female warrior who became Mulan's blood sister in the "Sui Tang Romance".