These notes and instructions only appear to people reading the template directly, when it is used you do not see this.

Note: This template is good enough to use on years after 1929. If you are planning to work on it to fix the issue of Julian display for years 1600 through 1929, it would be nice if you contact me, I might be able to help. Paul Robinson (Rfc1394) (talk) 20:25, 29 July 2013 (UTC)

The purpose of this template is to create a standard, uniform calendar description as the first sentence for all years, at least from 1600 on, with links to the appropriate terms. Currently, it works fine for 1930 and later; the Julian calculations need a bit of work. It's designed to say the year as either being "was" the year if it is before this year, "is" this year if it's the current year, and "will be" the year if it's after this year, e.g. in 2012, years 2011 and before would say "2011 was a common year starting on..." "2012 is the current year, and is a leap year starting on..." "2013 will be a common year starting on..."

Yes, it does know that only century years which are divisible by 400 are leap years.

Also, leave the space between "millennium" and the comma, it's a mnemonic to remind me it's a template and I need to fix (1) the before 1930 issue, and (2)add the letter representing leap year/exeptional/common year on day of week year starts in calcluations. (See the source code for 1997 for details where it's missing.)

{{Year article header|year it covers}} as the first item in the text of a year, e.g. {{Year article header|2092}} for the article for that year. Note that inserting the year directly as opposed to using {{PAGENAME}} was intentional; I needed to make calculations on the value passed and I wanted to make sure I could do that, plus I couldn't test the template if I used the PAGENAME parameter.

With very limited exceptions, because of bugs in PHP, this will probably not work before 1600. It currently does work perfectly for years after 1929 (1930 and later stopped using Julian Calendars; the Julian calculations need a bit more work). Years before 1582 show Julian and prospective Gregorian. 1582 shows Julian plus warning and prospective Gregorian, 1583 and later, Gregorian with Julian and number of days off for years below 1930, Gregorian only after 1929.