hanja rr article_title mr hangul
聖德王 seongdeok wang seongdeok of silla
 sŏngdŏk wang 성덕왕
seongdeok of silla

seongdeok daewang -lrb- reigned 702 -- 737 -rrb- 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 -lrb- queen seongjeong 成貞 -rrb- , 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 -lrb- which had actually launched a seaborne attack against tang in 733 -rrb- , in 733 the tang emperor xuanzong enfeoffed king seongdeok as military commander of ninghai -lrb- `` ninghai junshi '' 寧海軍使 -rrb- 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 a great wall 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 -lrb- and quite likely with the same laborers -rrb- seongdeok also had a large fortress erected near the capital of gyeongju that extended ten kilometers in circumference .
according to the samguk yusa , a 13th-century korean record of history and fable that deals with the period in question , the fortress -lrb- known as mobeol prefectural fortress -rrb- required the labor of nearly 40,000 men , a massive mustering of manpower that is testimony of the increasing power of the centralized monarchy .
the reign of seongdeok also bears evidence of continued attempts at reforming the land system of silla .
the dispersal of `` able -- bodied land '' -lrb- `` jeongjeon '' 丁田 -rrb- is first mentioned as taking place in the twenty -- first year of king seongdeok -lrb- 722 -rrb- .
the exact nature of able -- bodied land is disputed since almost no corroborating evidence remains .
however , based on the title , it would seem to be land distributed to able bodied commoners , though whether to work or own outright is unclear .
in any case , whatever its precise nature , it would appear to be an attempt to buttress royal authority by nurturing relations with the peasantry at the expense of the land holding aristocracy .
in fitting culmination to seongdeok ` s reign , and symptomatic of improving relations with tang , in 735 tang emperor xuanzong formally granted the silla king the territory south of the pae river -lrb- the modern taedong river running through pyongyang -rrb- , land that had been held at least formally by tang ever since the 7th century and the tang -- silla campaigns that had toppled goguryeo .
seongdeok ` s reign was one of relative prosperity and peace .
as one korean scholar has contended , during his rule '' ... the paramount authority of the throne was finally secured , and with this accomplished the kingdom at last was able to enjoy unaccustomed domestic tranquility . '' .
according to one account in the `` samguk sagi '' , seongdeok invented korea 's first water clock , in korean `` nugak '' 漏刻 , in 718 .
however , this is likely a mistaken rendering of nugakjeon 漏刻典 , for elsewhere the samguk sagi relates that in 718 was established for the first time the nugakjeon , or office of timekeeping .
regarding the death date of seongdeok , as period chinese histories record that in the second month of 737 a tang envoy was dispatched to confer investiture upon seongdeok 's successor -lrb- later king hyoseong -rrb- as king of silla , it has been posited that king seongdeok in fact died in 736 .
