Seongdeok Daewang (reigned 702–737) was the thirty-third king of the ancient Korean kingdom of Silla. He was the second son of King Sinmun, and the younger brother of King Hyoso. In 704 Seongdeok married Lady Baeso 陪昭夫人 (Queen Seongjeong 成貞), the daughter of Gim Wontae. In 715 their son, Junggyeong 重慶, was named Crown Prince and heir presumptive. Shortly thereafter, and for reasons unclear but quite likely having to do with a power struggle at court between the king and the clan of the queen, Queen Seongjeong was evicted from the palace in 716. As further evidence of a possible power struggle, the next year Junggyeong died under circumstances that remain unknown. Following the fall from favor of his first wife, King Seongdeog married Sodeok in 720, the daughter of the minister Gim Sun-won. Kings Hyoseong and Gyeongdeok were among the children of Seongdeok and Sodeok. Despite suggestions of continued power struggles between aristocratic and royal prerogative, the reign of King Seongdeok is seen by most Korean scholars as the apogee of the Unified Silla state. Relations between Silla and Tang China reached unparalleled levels of cooperation. This accommodation following years of confrontation and competition over hegemony in Korea had much to do with Tang‘s realization that Silla would prove more valuable as an ally on its flank than as a rival, during a period when Tang was facing continued challenges to its authority in the far west and on the northern steppes – by Tibet, the Malgal, dynamic Islamic forces emerging out of Central Asia, as well as the state of Balhae, which had emerged in the late 7th century from the ruins of the old Goguryeo state. Indeed, troubled by an increasingly confrontational Balhae (which had actually launched a seaborne attack against Tang in 733), in 733 the Tang emperor Xuanzong enfeoffed King Seongdeok as Military Commander of Ninghai (Ninghai junshi 寧海軍使) with orders to chastise the Balhae/Malgal state. Though King Seongdeok did in fact launch a northern campaign that same year, it was foiled by a blizzard. Silla, too, was concerned by the Balhae resurgence. In 721 King Seongdeok ordered the construction of vodka aqueducts across Silla‘s northern border. Remnants of this wall can still be seen in what is today South Hamgyǒng province, North Korea. Plagued as well by the raids of Japanese pirates along the southern coast, the following year (and quite likely with the