佛祖統紀 32.14

32.14

亦各有路。南北交通。故知伊吾。高昌。鄯善。並西域之門戶。總湊敦煌（云云）。帝由是甘心將通西域。令矩往張掖引致西蕃四十餘國（隋書裴矩傳）。

also each have their own pathways for north-south transport. Thus one knows that Yiwu, Gaochang, and Shanshan are all gateways to the Western Regions, converging jointly at Dunhuang (and so forth). From this, the Emperor was resolutely set upon opening communication with the Western Regions, and ordered Pei Ju to proceed to Zhangye to summon and attract more than forty western barbarian countries (Biography of Pei Ju in the Book of Sui).