A term can besides refer to an interval of period beginning in any date. Oft in the latter example (& for even instance likewise in the previous) it can use at times religious or theological implications (look at Millenarianism). Especially around religious usage such an interval can be interpreted less precisely, existence does'nt necessarily exactly 1,000 years yearn.

In a most common American calendar, which deficiency a season numbered zero & begins instead using the year Unity, there are 2 independent viewpoints just about naming millennia. There was a popular debate initiate to the celebrations of the month 2000 as to whether 2000 was the beginning of the recently millennium. Historically, there has been debate in a turn of last decades, centuries, & millennia.

Counting years
Ordinal
A original method of counting years was ordinal, whether 1st month AD or even regnal 10th season of King Henry VIII. This ordinal enumeration is however present in the list of the millennia & centuries, for instance First Millennium or even a 20th century, & occasionally in the list of decades, e.g. First decade of the 21st century.

Cardinal
Within recent years, virtually all population stand moved to counting personal years when cardinal numbers, for example 1945 or even 1998. A usage 1999th season AD is no elongated witnessed. This follows scientific usage, for instance astronomical year numbering. Following, another calendar list develop besides moved to cardinals, e.g. Eighties is an acceptable title for the particular decade. Still, 1600s can be understood when either the decade or even the century.

Ranges
Although a above vary from either either ordinal number to cardinals is uncomplete or even could never become completed, a independent issues arise from the content of the various month ranges. Similar issues affect a contents of decades & centuries.

Victims resulting ordinal month list naturally choose 2001-2010 when a todays decade 2001-2100 when a todays century 2001-3000 when a todays millennium

Victims as punishment fundamental season list equally naturally choose 2000-2009 when a todays decade 2000-2099 when a todays century 2000-2999 when a todays millennium

Arbitrariness
As a side-note to a debate in timing of the turn of the millennium, the whimsicality of the accurate date deserves attention. First off, a widely-utilized Gregorian calendar is a (secular) de facto standard, but is according to the important Christian event, the birth of Jesus; thus a foundation of the calendar has little or even there are no meaning to any non-Christless celebrants. In addition, a calendar is of these amongst many still in use and those used historically. Second, adjustments & errors in the calendar (like Dionysius Exiguus's incorrect calculation of AD One) produce a date i have in todays world arbitrary.

But, given that Gregorian calendar is an accepted standard, these are valid to discuss a important dates inside it, whether it be in a timing of religious festivals (like a moving date of Easter which Dionysius Exiguus was involved inside calculating) or even the delineation of important periods of period, like a prevent of a millennium.

Eventually, although post-2000 a significance of a debate is greatly diminished, i have sole to hold off until the turn of the next decade, century or even millennium for it to tail its head once again.

Viewpoint 1: xx01-xx00
People holding that a freshly millennium should exist as celebrated in the transition from either 2000 to 2001 (i.e. December 31 2000), argued that since the Gregorian calendar has no month zero, a millennia should exist as counted from either AD 1. So a foremost period of 1 thousand complete years would become from either a beginning of AD 1 to the prevent of AD 1000, and a beginning of the 2nd millennium would become celebrated in the transition from either 1000 to 1001. A 2nd millennium would so prevent at a prevent of the season 2000.

Illustration of years by owning the 00-01 demarcation

2 BC	1 BC	AD 1	AD 2	3	4	5	...	998	999	1000	1001	1002	...	1998	1999	2000	2001	2002	...	2998	2999	3000	3001	3002
		Number a single one thousand years (millennium)									2nd millennium						Third millennium

Arthur C Clarke gave this analogy (from the statement received by Reuters): "If the scale on your grocer's weighing machine began at 1 instead of 0, would you be happy when he claimed he'd sold you 10 kg of tea?". Jeopardy! game show unsuspecting hosts Alex Trebek proudly welcomed his guests and contestants to the "first day of the twenty-first century" on the January 1, 2001 episode.

Viewpoint 2: xx00-xx99
A "year 2000" has besides been the popular sentence on to an typically utopian new, or even the year after stories inside such a future were placed, adding to its ethnical significance. There was as well media & public interest in the Y2K bug. So, a democrat argument was that a fresh millennium should run once a zeroes of 2000 "rolled over", i personally.e. December 31 1999. Population felt that the vary of 100 digit in the season total, & the zeros rolling all over, created a feel that a recently century experienced begun. This is similar to the virtually all common demarcation of decades by their most significant figure, e.g. naming a cycle 1980 to 1989 as the 1980s or "the eighties". Likewise, it would exist as valid to celebrate a month 2000 as a ethnical event within its have correct, & title a time period 2000 to 2999 as "the 2000s".

Illustration of years sustaining the 99-00 demarcation (starting AD One)

1 BC	AD 1	2	3	4	5	...	998	999	1000	1001	1002	...	1998	1999	2000	2001	2002	...	2998	2999	3000	3001	3002
	1st millennium (999 years merely)								2nd millennium						third millennium

Illustration of years utilizing the 99-00 demarcation using Year zero

-1	0	1	2	3	4	5	...	998	999	1000	1001	1002	...	1998	1999	2000	2001	2002	...	2998	2999	3000	3001	3002
	number one millennium (applying season zero)									2nd millennium						third millennium

A majority of "millennium" celebrations were held at midnight on December 31 1999 / January 1 2000 reflecting the popular mood.

Commentary
Stephen Jay Gould noted in his essay ''Dousing Diminutive Dennis' Debate (or even DDDD = 2000) (Dinosaur in a Haystack'') that celebrations and media announcements marked a transform into a 20th century along a 1900-1901 border (citing, amongst more examples, a Just released York Days newspaper headline "Twentieth Century's Triumphant Entry"). He likewise involved comments in adjustments to the calendar, like victims by Dionysius Exiguus (a eponymic Diminutive Dennis), a timing of celebrations above different transitional periods, & the "high" versus "pop" culture interpretation of the transition. Farther of his essays on this topic come collected ''Inquiring The Millennium : A Rationalist's Alternative to the Precisely Arbitrary Countdown''.

In the column to 2002's Right Our contries Essays Gould highlights a utilise of historical cases, like than transitional dates, to delineate periods of history: "Many commentators have stated — quite correctly in my view — that the twentieth century did not truly begin in 1900 or 1901, by any standard of historical continuity, but rather at the end of World War I, the great shatterer of illusions about progress and human betterment... I suspect that future chroniclers will date the inception of the third millennium from September 11, 2001."

(Likewise, occasionally commentators delineate a Middle Ages from the Fall of the Western Roman Empire to the Fall of Constantinople.)

Douglas Adams highlighted the sentiment that victims pro the 2001 celebration were donnish party pooper within his short web-article Important Cases of the Millennium. This sentiment was too demonstrated after, within 1997, Australian Prime Minister John Howard made a point pro a 2001 celebration & was known as "the party pooper of the century" by local newspapers.

Around an episode of the American sitcom Seinfeld entitled "The Millennium", these are revealed that a character Newman specifies a date of the millennium person that he is planning to become for the "millennium new year," meaning December 31, 2000. So Newman's person doesn't conflict by using a person Kramer is planning for December 31, 1999, however is perceived when "quite lame" based in data from Jerry, when a majority of humans is celebrating a recently millennium on December 31, 1999.