In 272, at age 12, Crown Prince Zhong married Jia Chong's daughter Jia Nanfeng, who at 14 was two years older. Crown Princess Jia was violent and jealous, but had her methods of controlling Crown Prince Zhong so that he both loved and feared her. She bore him four daughters during their marriage, but she would not bear his only son Sima Yu – whose mother Consort Xie Jiu was originally a concubine of Emperor Wu, but had been given to Crown Prince Zhong prior to his marriage to Crown Princess Jia, so that Consort Xie could teach him how to have sexual relations. Consort Xie became pregnant and bore Sima Yu, who was much favored by his grandfather Emperor Wu. Emperor Wu considered Prince Yu intelligent and very much like his own grandfather Sima Yi, and this played into his decision not to replace Crown Prince Zhong. However, other than Consort Xie, no other concubine would bear Crown Prince Zhong a child—as several had been pregnant but each was murdered by Crown Princess Jia, in fits of jealousy. (Emperor Wu, in anger, considered deposing Crown Princess Jia, but with the intercession of his second wife Empress Yang Zhi, he recalled Jia Chong's contributions to the establishment of Jin Dynasty, and decided to leave her in place.)