佛祖統紀 36.70

36.70

述曰。此土沙門西遊者始於朱士行。而唯及於西域于闐。實葱河之東境耳。至顯師則西踰葱嶺遠屆五天。復能取道南海東還晉地。求法之勤以此師為始也。

The commentary states: Śramaṇas of this land traveling to the west began with Zhu Shixing, yet he only reached Khotan in the Western Regions, which was in fact the territory east of the Pamir River (Conghe). But when it came to Master Faxian, he crossed the Pamir Mountains (Congling) to the west and reached far into the Five Indias, and was further able to take the route across the southern sea to return east to the land of Jin. The diligent quest for the Dharma truly began with this master!