佛祖統紀 42.82

42.82

述曰。此方往五天者有二道焉。其一為西北路。自敦煌陽關經西域諸國。過葱嶺雪山入北天竺境。自昔漢騰蘭西來。唐奘師等東往之所經由是也。其二為西南路。自南海發舶至佛逝國羯茶國。西北至耽摩國東天竺境（是東竺南界。即海口升舶歸唐之所）自昔梁達磨西來。淨三藏會寧東往之所遊歷者是也。今鉢怛羅至蜀之路。乃當正西。即張騫所謂大夏東南去蜀不遠之說。比之兩路宜應稍近。而今所經歷約十萬里者。當是山川盤折。風俗不通。取道紆回。故十有餘年方得至蜀。以故來者。僅一鉢怛羅。而此方絕無一人取此路也。

I observe: There are two routes from this land to the Five Indias. The first is the northwestern route: from Yangguan in Dunhuang, passing through the various kingdoms of the Western Regions, crossing the Pamir Mountains and the Snow Mountains to enter the territory of North Tianzhu. This is what was traveled formerly when the Han masters Mātanga and Dharmaratna came from the west, and when the Tang master Xuanzang and others went to the east. The second is the southwestern route: embarking on a ship from the Southern Sea to the kingdoms of Śrīvijaya and Kaṭāha, and heading northwest to the kingdom of Tāmralipti, the territory of East Tianzhu (this is the southern border of East Tianzhu, the seaport where one embarks on a ship to return to the Tang). This is what was traveled formerly when Bodhidharma of the Liang came from the west, and when the Tripiṭaka master Yijing and Huining went to the east. Now the route by which Pātra arrived in Shu lies due west; this corresponds to Zhang Qian's statement that Bactria is not far to the southeast of Shu. Compared to the two routes, it ought to be somewhat closer. That he has now traveled approximately one hundred thousand li must be because the mountains and rivers wind and twist, local customs do not communicate, and the route taken was roundabout, so that it took more than ten years to reach Shu. For this reason, of those who have come, there has only been this one person, Pātra, while from this land not a single person has ever taken this route.