Thus subdued, Sun would not have been able to get out of his stone prison but for the intercession of Kuan Yin P’u-sa, who obtained his release on his solemn promise that he would serve as guide, philosopher, and friend to Hsüan Chuang, the priest who was to undertake the difficult journey of 108,000 li to the Western Heaven. This promise, on the whole, he fulfilled in the service of Hsüan Chuang during the fourteen years of the long journey. Now faithful, now restive and undisciplined, he was always the one to triumph in the end over the eighty-one fantastical tribulations which beset them as they journeyed. Page 334