Today is a special day - it is the 18th of December 2007 as reckoned by the Julian calendar and there is one week to go until Christmas.
Of course as reckoned according to the Gregorian Calendar it is the 31st of December and therefore the last day of 2007. And since this is the calendar recognized by our civil authorities and the only one known to the majority of us, we will all celebrate the new year tonight and recover tomorrow.
It is long forgotten but the English speaking world used to begin the new year on the 25th of March. The change came in 1751 when Great Britain adopted the Gregorian Calendar, a matter of no import except to historians who if they don't watch themselves can get caught out as to the year in which a particular event occurred if it happened in January, February or March in the years before 1751.
The AD/BC designation for years (or more formally "Anno Domini Nostri Iesu Christi" and "Before Christ") was first devised in the 5th century has been in common use throughout Europe since the 8th. This system has now become a relic from our unsophisticated past. Amongst the enlightened it has been replaced be CE/BCE. CE stands for Common Era or occasionally it is said to stand for Christian Era. It is easy to translate between the two systems, the actual number remains the same, all that is required is to drop the AD from the front and replace it with a CE to the rear. A process the labels on most museum exhibits have already undergone.
The CE/BCE system for designating years may not last long. The ancient city of Oxford, a town that owes its very existence to Christian scholarship, is engulfed in controversy over the ringing of church bells and the imams call to prayer being broadcast through loud speakers from a local mosque.
Who knows how that one will play out but pity the poor museum curators - sometime in the future they are likely to be required to translate all the dates on their exhibits yet again. And translating dates from the Gregorian calender to those of the Islamic lunar calender is a lot more tricky than dropping AD from the front of the number and replacing it with CE to the rear.
To assist Microsoft has produced the Kuwaiti algorithm which can translate Gregorian dates to those of the Hijri (Islamic) calendar, well sort of.
But I wouldn't be at all surprised that even with the software the process produces more headaches than tonights New Years eve over indulgence.