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 the intended design objective. The tabular forerunner to Tøndering's algorithm is embodied in the following K&R C function. With minor changes, it was adapted for other high level programming languages such as APL2. Posted by Tomohiko Sakamoto on the comp.lang.c Usenet newsgroup in 1992, it is accurate for any Gregorian date. IBM's Rata Die method requires that one knows the "key day" of the proleptic Gregorian calendar i.e. the day of the week of January 1, AD 1 (its first date). This has to be done to establish the remainder number based on which the day of the week is