Battle of Ba Dau (Vietnamese language: tráºÂn Ba ÃÂầu or tráºÂn bến Ba ÃÂầu) was in year 1128 between ÃÂại Viá»Ât under the Ly dynasty and Khmer Empire at Nghá» An, the south of ÃÂại Viá»Ât. Result of battle is the victory of the Ly dynasty. This is the very first conflict between the two countries which later escalated into the ÃÂại Viá»ÂtâÂÂKhmer War that lasted until 1150.
Since the beginning of the Lý dynasty, ÃÂại Viá»Ât and Khmer empire had many diplomatic exchanges. In this relationship, Khmer was in the position of a vassal state, obliged to pay tribute to ÃÂại Viá»Ât, with the first tribute taking place in 1012, under emperor Lý Thái Tá»Â. After being enthroned in 1113, Suryavarman II of the Khmer empire soon launched multiple campaign to expand its territory. With ÃÂại Viá»Ât, Suryavarman II paid tribute once, in 1120.
In January 1128, Lý Dðáng Hoán became the emperor with the era name of Thiên ThuáºÂn. In that same month, more than 20,000 Khmer troops (known as Chenla to the Vietnamese at this time) raided the Ba ÃÂầu port in Nghá» An province. The emperor issued an imperial edict assigning general Lý Công Bình to lead the army in Nghá» An to counter the attack from the Khmer. In February 1128, Lý Công Bình defeated the Khmer troops and captured their chief commander along with the remnant forces. Upon receiving news of the victory, the emperor performed several rituals in Thái Thanh and Cảnh Linh palaces, as well as in several pagodas inside the capital, to thank Heaven and Buddha for blessing the triumph. That act was criticized by historian Lê VÃÂn Hðu for showing insufficient respect to the general and soldiers who fought in the war.
Later in March 1128, Lý Công Bình led his troops back to the capital and presented 169 captives to the imperial court. That marked the end of this battle as the first conflict between two countries.
There are no historical records of the casualties on either side. The two countries refused to make peace after the conflict, as another raid by the Khmer Empire against ÃÂại Viá»Ât broke out in August of the same year. The Khmer empire ceased paying tribute to ÃÂại Viá»Ât after this conflict, since several subsequent clashes broke out between the two countries, later known as the ÃÂại Viá»ÂtâÂÂKhmer War.
In The Ancient Khmer Empire (1951), Lawrence Palmer Briggs claimed that Suryavarman II personally led the battle of Ba ÃÂầu, whereas no Vietnamese historical record such as ÃÂại Viá»Ât sá» ký toàn thð mentions the presence of the Khmer emperor in that battle. Since Vietnamese historical record states that the chief commander was captured in the battle, Suryavarman II was likely not present, or he may have successfully fled when his troops were defeated.
In August 1128, 700 Khmer ships raided the town of Hðáng Gia in Nghá» An but were defeated by the ÃÂại Viá»Ât's army. The people of Nghá» An province then submitted a petition to the emperor, requesting an envoy be sent to the Khmer Empire to make peace, but the emperor gave no reply. Tensions continued between the two countries.