https://en.wikipedia.org/wiki/Soča
Name. The river was recorded in antiquity as Aesontius, Sontius, and Isontius.Later attestations include super Sontium (in 507–11), a flumine Isontio (1028), in Lisonçum (1261), an die Ysnicz (1401), and an der Snicz (ca. 1440). The Slovene name Soča is derived from the form *Sǫťa, which was borrowed from Latin (and Romance) Sontius.In turn, this is probably based on the …