Maundy Thursday normally celebrated in the evening, when Friday begins according to Jewish tradition, as the Last Supper was held on the feast of Passover, according to the three Synoptic Gospels. Use of the names "Maundy Thursday", "Holy Thursday", and others is not evenly distributed. What is the generally accepted name for the day varies according to geographical area and religious affiliation. Thus, although in England "Maundy Thursday" is the normal term, the term is less commonly used in Ireland, Scotland or Canada. People may use one term in a religious context and another in the context of the civil calendar of
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