The Old English poem Widsið contains a curious reference to the *Seringas (nom. sing. *Sering, nom. pl. *Seringas, attested in the poem by the dative plural Seringum at line 75), a people of unknown identity. This might have be the earliest reference to the Chinese people in Germanic literature.
The word looks like something borrowed from L. Seres (sing. *Ser hardly attested in Latin -- it's a collective noun anyway). The -ing ending, which is ultimately derived from the PGmc suffix -ingaz, has the meaning of "people, tribe, or lineage belonging to something."
Even if we read *Seringas as the loanword from Latin Seres, it is difficult to establish the ethnic identity of this people. No classical source could unambiguously identify the Seres as ancestors or predecessors of today's Chinese people.
The poet Virgil, who might have had some influence on Germanic epic literature, mentions the Seres as a people known for silk production by "combing off the trees" in his Georgics, in the same passage with "Ethiopia" and "India." This doesn't say much about the poet's grasp of their geographical identity. Virgil's contemporary Strabo, and their successor Pliny the Elder, describe the Seres as a people inhabiting the eastern lands and an exporter of silk. To the Greco-Roman, the Seres might refer to either the Chinese, or a silk-road people trading with the Chinese.
Anyway, we don't know much about the Anglo-Saxon poet's intention here. Widsið displays an anachronistic, repetitive, and outright fantastic account of the nations of the earth as they were known to a learned Anglo-Saxon. For the poet, just like for his remote predecessor Virgil, the identities didn't matter. What mattered was their exotic nature, something that lived beyond the bounds of the Germanic (or Roman) world.