Wednesday "Germanic Mercury". The Latin name dates to the late 2nd or early 3rd century. It is a calque of Greek ("heméra Hérmou"), a term first attested, together with the system of naming the seven weekdays after the seven classical planets, in the "Anthologiarum" by Vettius Valens (c. AD 170). The Latin name is reflected directly in the weekday name in most modern Romance languages: "Mércuris" (Sardinian), "mercredi" (French), "mercoledì" (Italian), "miércoles" (Spanish), "miercuri" (Romanian), "dimecres" (Catalan), "Marcuri" or "Mercuri" (Corsican). In Welsh it is Dydd Mercher, meaning Mercury's Day. The German name for the day, "Mittwoch" (literally: "mid-week"), replaced the
Names of the days of the week seven-day week spread throughout the Roman Empire in Late Antiquity. By the 4th century, it was in wide use throughout the Empire, and it had also reached India and China. The Greek and Latin names are as follows: Except for modern Portuguese and Mirandese, the Romance languages preserved the Latin names, except for the names of Sunday, which was replaced by "[dies] Dominicus (Dominica)", i.e. "the Lord's Day" and of Saturday, which was named for the Sabbath. In Corsican, the Saturday is known either by Sabatu or De Sadorn. Early Old Irish adopted the names from Latin, but introduced separate