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
Determination of the day of the week Determination of the day of the week The determination of the day of the week for any date may be performed with a variety of algorithms. In addition, perpetual calendars require no calculation by the user, and are essentially lookup tables. A typical application is to calculate the day of the week on which someone was born or a specific event occurred. In numerical calculation, the days of the week are represented as weekday numbers. If Monday is the first day of the week, the days may be coded 1 to 7, for Monday through Sunday, as is practiced in