Wu Chengsi and another nephew of Wu Zetian's, Wu Sansi the Prince of Liang, are making repeated attempts to have officials persuade Wu Zetian to create one of them crown prince—again citing the reason that an emperor should pass the throne to someone of the same clan.

However, Di Renjie, who by now has become a trusted chancellor, is firmly against the idea and instead proposes that Li Zhe be recalled.

He is supported in this by fellow chancellors Wang Fangqing and Wang Jishan, as well as Wu Zetian's close advisor Ji Xu, who further persuades the Zhang brothers to support the idea as well.

In spring 698, Wu Zetian agrees and recalls Li Zhe from exile.

Soon, Li Dan offers to yield the crown prince position to Li Zhe, and Wu Zetian creates Li Zhe crown prince, soon changing his name back to Li Xiǎn and then Wu Xian.

Later, Ashina Mochuo demands a Tang dynasty prince for marriage to his daughter, part of a plot to join his family with the Tang, displace the Zhou, and restore Tang rule over China (under his influence).

When Wu Zetian sends a member of her own family, grandnephew Wu Yanxiu, to marry Mochuo's daughter instead, he rejects him.

Ashina Mochuo has no actual intention to cement the peace treaty with a marriage; instead, when Wu Yanxiu arrives, he detains Wu Yanxiu and then launches a major attack on Zhou, advancing as far south as Zhao Prefecture (in modern Shijiazhuang, Hebei) before withdrawing.

The Tufan threat ceases in 699.

The Tufan king Tridu Songtsen, unhappy that Lun Qinling is monopolizing power, takes an opportunity when Lun Qinling is away from the capital Lhasa to slaughter Lun Qinling's associates.

He then defeats Lun Qinling in battle, and Lun Qinling commits suicide.

Lun Zanpo and Lun Qinling's son Lun Gongren surrender to Zhou.

After this, Tufan will experience internal turmoil for several years, and there will be peace for Zhou on the Tufan border.

Also in 699, Wu Zetian, realizing that she is growing old, fears that after her death, Li Xian and the Wu clan princes will not be able to have peace with each other, and she compels him, Li Dan, Princess Taiping, Princess Taiping's second husband Wu Youji (a nephew of hers) the Prince of Ding, and other Wu clan princes to swear an oath to each other.

…Chengde (headquartered in modern Shijiazhuang, Hebei), governed by Wang Yuankui; and …

…Emperor Taizong dies of a sudden illness, just south of modern-day Shijiazhuang, Hebei.