Three years before this, in 372, the Chinese had gained a signal victory over the Yŭn kingdom and its king, Mo Yong-p’ung, had fled for safety to Ko-gu-ryŭ. It must have been his last resource, for he was likely to find little sympathy there. And so it proved for the king immediately seized him and sent him a captive to China.
The year 372 beheld an event of prime importance in the history of Ko-gu-ryŭ and of the whole peninsula. It was the introduction of Buddhism. It is probable that before this time some knowledge of Buddhism was current in Korea, but as it is eminently a sacerdotal institution but little more than indefinite reports could have been circulated previous to the coming of the monks. We are not told whether this was done at the request of Ko-gu-ryŭ or whether it was at the advice of Pu-gyŭn, one of the petty kings who then divided between them the north of China. Be that as it may, in 372 A.D. images of Buddha were brought by a monk, Sun-do, and also a Buddhist book called Pul-gyŭng. For this the king of Ko-gu-ryŭ returned hearty thanks and forthwith set his son and heir to learning the new doctrine. At the same time he gave an impetus to the study of the Confucian code. It is quite probable that to this new departure is due the fact that the next year the laws of the country were overhauled and put in proper shape for use. In 375 two great monasteries were built in the capital of Ko-gu-ryŭ. They were called Cho-mun and I-bul-lan. It should be noticed that the introduction of Buddhism into Korea was a government affair. There had been no propagation of the tenets of this cult through emmisaries sent for the purpose, there was no call for it from the people. In all probability the king and his court were pleased at the idea of introducing the stately ceremonial of the new faith. In fact it was a social event rather than a religious one and from that date to this there has not been a time when the people of Korea have entered heartily into the spirit of Buddhism, nor have her most distinguished representatives understood more than the mere forms and trappings of that religion which among all pagan cults is the most mystical.
Păk-je was not long in following the example of her powerful neighbor. In the year 384 a new king ascended the throne of Păk-je. His name was Ch’im-yu. One of his first acts was to send an envoy to China asking that a noted monk named Mararanta be sent to Păk-je to introduce the Buddhist ritual. We notice that this request was sent to the Emperor Hyo-mu (Hsia-wu), the proper head of the Eastern Tsin dynasty, while Ko-gu-ryŭ had received hers at the hands of one of those petty kings who hung upon the skirts of the weakening dynasty and waited patiently for its dissolution. Each of these petty states, as well as the central government of the Tsin, was on the lookout for promising allies and such a request as this of Păk-je could scarcely be refused. Mararanta, whose name smacks of the south and who certainly cannot have been a Chinaman, was sent to the Păk-je capital. He was received with open arms. His apartments were in the palace where he soon erected a Buddhist shrine. Ten more monks followed him and Buddhism was firmly established in this second of the three Korean states. The greatest deference was paid to these monks and they were addressed by the honorific title To-seung. Sil-la received Buddhism some fifty years later.