The Song is considered a high point of classical Chinese innovation in science and technology, an era that featured prominent intellectual figures such as Shen Kuo and Su Song and the revolutionary use of gunpowder weapons. However, it was also a period of political and military turmoil, with opposing and often aggressive political factions formed at court that impeded political, social, and economic progress. The frontier management policies of the Chancellor Wang Anshi exacerbated hostile conditions along the Chinese-Vietnamese border. This sparked a border war with Vietnam's Lý dynasty, which was fought to a mutual draw and concluded with a peace treaty in 1082. To the northwest the Song Empire frequently quarreled with the rival Western Xia, led by the Tanguts, as well as the Liao Dynasty to the northeast, led by ethnic Khitans.