korea 113he attempted to take a strong line with Koguryo and invited its king,
Kao Yüan, to come to his court. The king naturally refused, but
hardly out of fear as claimed by the texts (Sui shu 81:4b; Wen-hsien
t’ung-k’ao 325:49b).
In the 8th month (Aug./Sep.) of 607, Emperor Yang, to no avail,
reminded Koguryo envoys that he expected their king to arrive at his
court (Sui shu 3:11a).
On May 14, 609, a mission from Koguryo called on Emperor Yang
in northwestern China while he was preparing for an attack on the
T’u-yü-hun (Pei shih 12:13a).
Emperor Yang’s foiled expectations led to a new conflict of arms,
conducted in three campaigns. The first, in 612, supported by Paekche,
led to a small territorial gain for Sui in which the Liao River became
the border between China and Koguryo. The second, in 613, had to
be aborted because of a rebellion in China. In the third, in 614, Sui
troops reached P’ongyang but were unable to take it. The war ended
in another standoff and was worth neither the investment nor the
result. Another attempt by Emperor Yang to bring Kao Yüan to his
court failed, as it was bound to do (Sui shu 81:5a; Wen-hsien t’ung-k’ao
325:49b).
In Koguryo, Kao Yüan was in 618 succeeded by his brother Kao
Chien-wu (Yongnyu Wang).^4 In 619, his envoys came to the T’ang
court (Chiu T’ang shu 199A:1b; Ts’e-fu yüan-kuei p.5023).
In the 7th month (July/Aug.) of 621, Koguryo envoys offered
gifts. They furthermore requested instruction in Taoism, whereupon
Chinese Tao masters were dispatched to their country (Chiu T’ang shu
199A:1b;Ts’e-fu yüan-kuei p.5023; Tzu-chih t’ung-chien p.5923; Wen-hsien
t’ung-k’ao 325:50a).
In 622, envoys from Koguryo arrived again at the T’ang court (Ts’e-
fu yüan-kuei p.5023). That same year, T’ang and Koguryo reached an
agreement to exchange nationals. Many Chinese, including warriors
of the defeated Sui armies, were living in Koguryo, while Koreans
from Koguryo stayed in various parts of China. These were to be
repatriated (Chiu T’ang shu 199A:1b; Tzu-chih t’ung-chien p.5964).
In the 12th month (Dec./Jan., 624) of the Chinese year 623, Kogu-
ryo envoys offered presents (Ts’e-fu yüan-kuei p.5023).
On Mar.1, 624,envoys from the king of Koguryo, Kao Chien-
(^4) The Imperial Annals of Chiu T’ang shu refer to him throughout as Kao Wu.