In English salsa verde literally translates as green sauce. This can be the cause of some confusion because there are many green sauces in this world. Wikipedia cites five variations and suggests a shared history for the European versions:
The basic recipe is probably from the Near East and, as such, is probably at least 2,000 years old. Roman legionaries brought it to Italy, from where it was exported to France and Germany. Evidence suggests that it was introduced in Frankfurt am Main by the Italian trading families Bolongaro and Crevenna around 1700. A possible origin of the German variant are French Protestant immigrants emigrating to Kurhessen in the 18th century.
In this post, I am dealing with the Italian version.