Claudius Ptolemy wrote Geography, describing regions east of the Roman world including Serica.
Ptolemy was a Greek-speaking scholar active in Alexandria during the second century CE. His Geography, usually dated to about 150 CE, compiled geographic information from earlier writers, travelers, merchants, and maps. It presented coordinates and descriptions for places known to the Greco-Roman world.
The work refers to Serica, a distant eastern land associated with silk and the people known as the Seres. Ptolemy also described routes and places connected with the broader commercial world reaching toward Central Asia and China, although his eastern information was uneven and sometimes based on indirect reports.
Ptolemy did not describe the Silk Road as a named unified route; that modern term was coined much later. His Geography is valuable because it preserves evidence of how Roman-era scholars understood far-eastern trade and geography, despite substantial errors in distances and locations.