How a fractured Korean alliance turned against its Chinese superpower patron to secure independence.
After helping the Tang dynasty conquer their rivals, the kingdom of Silla found itself under threat of occupation. In a daring reversal, Silla united former enemies to expel the Tang forces, fundamentally reshaping the map of the Korean Peninsula and establishing a sovereign state that would endure for centuries.
The Silla–Tang War (670–676) emerged from the collapse of a fragile alliance. Initially, Silla and the Tang dynasty joined forces to dismantle the kingdoms of Baekje and Goguryeo. However, once the conquest was complete in 668, the Tang betrayed their agreement with Silla. Emperor Gaozong reneged on promises made by his predecessor, Taizong, to cede territories south of Pyongyang. Instead, the Tang established the Protectorate General to Pacify the East, forcibly resettling local populations and dividing former Goguryeo lands into dozens of commanderies and prefectures.
King Munmu of Silla responded by forging a new coalition, incorporating remnants of the Baekje and Goguryeo military alongside his own forces. This resistance was bolstered by persistent uprisings within the occupied territories, which began in 669. By 671, Silla had successfully pushed Tang forces out of most of Baekje’s former lands. The conflict intensified as both sides traded victories and defeats, including the pivotal Battle of Maeso in 675. While traditional accounts describe a massive Silla victory, modern scholars like Kim Byeong-Hee suggest the Tang were already retreating due to logistical strain and the need to redeploy troops to the Tibetan frontier.
The war concluded in 676 after a final naval engagement at Gibeolpo. The resulting truce established a new border along the Taedong River, with the Tang retreating to Liaodong and Silla securing control over the majority of the Korean Peninsula. This outcome effectively ended Tang imperial designs on Silla. Diplomatic relations remained severed until the early 8th century, eventually leading to formal Tang recognition of Sillan sovereignty in 736. While Silla failed to reclaim northern Goguryeo territories—which later fell to the state of Balhae—the war successfully preserved Silla’s autonomy, defining the geopolitical boundaries of the region for generations.
Source: Silla–Tang War
