In the 760s when Emperor of Gaozong of the Tang Dynasty was in the reign, a series of significant events happened in the Korean Peninsula, including the downfall of the Baiji kingdom, hard fighting between the Tang garrison in Xinluo and the reviving troops of Baiji, the battle at the mouth of the Bai River, and the perish of the Gaoli kingdom. In face of the military actions of the TangXinluo allies to Baiji, Gaoli as an important side in the negotiation between the Tang Dynasty and Korean Peninsula coped weakly with the allies’ actions to annihilate Baiji because it had to deal with continuous pressures from the Tang Dynasty and Xinluo and with acute internal contradictions. Even worse, it watched the annihilation of the reviving troops of Baiji without offering any help and was silently absent from the battle at the mouth of the Bai River attempting to take some unexpected gain. At the critical moment of radical changes in the peninsula, Gaoli gave up its former tough and hightuning strategies and became inactive and incapable, which sped up its downfall in the end. In face, Gaoli's clearly different tactics in coping with its relations with the Tang Dynasty in the early and later days led necessarily to its final downfall.

foreign relations in the Tang Dynasty; the Korean Peninsula; Gaoli; Xinluo; Baiji