But he did say that the next Summer Games, in Sydney in 2000, would be the first Olympics of the 21st century and of the new millennium.

On the second point, at least, Samaranch was wrong.

So were the pundits who wrote in our newspapers last fall that the Clinton-Dole-Perot race was the last presidential campaign of the 20th century. Yet Bill Clinton was right, chronologically anyway, when he promoted his second term (which ends in January 2001) as a bridge to the 21st century.

As we rush headlong toward the end of the 20th century and the beginning of the 21st, it is time to consider just when that event occurs.

You heard it here first:

The 20th century and the second millennium end at midnight Dec. 31, 2000, and the 21st century and third millennium begin in the next instant.

You may have noticed that thousands of people are already booking party reservations for New Year's Eve 1999.

They'll celebrate a momentous event, all right, as all the digits change for the first time in a thousand years, like the zeroes lining up on the odometer of a durable automobile. But as big a party as that is going to be, the revelers will not greet the arrival of a new century and millennium that night.

You don't have to take my word for this. All you have to do is accept a couple of easily verifiable facts, and then do some elementary arithmetic. The facts are:

1. A century equals 100 years.

2. There was no year 0; we went from 1 B.C. to 1 A.D.

The first century A.D., then, lasted from year 1 to year 100. The second century lasted from 101 to 200. And so on down the centuries, until the present century, which began in 1901 and lasts through 2000.

If you don't want to bother with the arithmetic, you can consult to some impressively authoritative sources. The U.S. Naval Observatory's Nautical Almanac Office, which is the nation's official timekeeper, announced in a two-page white paper in the 1980s: "The 21st century will begin with 1 January 2001 and continue through 31 December 2100." And a private Web site in Greenwich, England, dedicated to the subject not only confirms that the new century starts on Jan. 1, 2001, but further notes that Greenwich and other places on the Prime Meridian of the World will be the first to greet the new century. That is because an international conference decided in 1884 that every day officially begins on the Prime Meridian.

All this seems simple enough. The trouble is that Señor Samaranch, the pundits who write in our papers, and just about everyone else on the planet think otherwise. To the extent, of course, that they have thought about it all.

If history is a guide, they will start thinking about it increasingly - but not necessarily all that clearly - in the next three years, and the confusion will perplex newspapers and their readers. Ruth S. Freitag of the Library of Congress has compiled a list of more than 200 pamphlets and articles showing that there was a furious debate on this subject at the end of the 17th, 18th and 19th centuries. In a press release announcing the publication of Freitag's booklet, "The Battle of the Centuries," the Library says: "When does a century end? This simple question has such a simple answer that the very existence of a dispute is puzzling."

Freitag writes: "The source of the confusion is easy to discern; ever since learning how to write, we have dated our documents with year designations beginning with the digits 19. Obviously, when we must begin to date them starting with 20, we have embarked on a new century! Haven't we? The answer is no, we have not; we have merely arrived at the last year of the 20th century."

The late LeRoy E. Doggett, writing in the U.S. Naval Observatory's pamphlet, recounted how the sixth century scholar Dionysius Exiguus linked existing tables of dates and decided that his new, comprehensive table would count the years from the birth of Jesus Christ. "Today it is obvious," Doggett wrote, "that a year designated 1 would be preceded by year 0, which would be preceded by year -1, etc. But ... the concept of negative numbers did not come into use in Europe until the sixteenth century." (Had Dionysius used 0 for the year of Christ's birth, each century would begin with a 00 year and end with a 99 year, and things would be much simpler for journalists.)

Although Dionysius' new table accurately aligned the existing systems of historical records, he failed to establish an accurate date for the birth of Christ. Doggett wrote: "While scholars generally believe that Christ was born a few years before A.D. 1, the records are too sketchy to allow a definitive dating."

Freitag's booklet mentions that "those who are unwilling to accept the clarity of simple arithmetic" have argued that Dionysius' mistake allows them to celebrate the beginning of a new century a year early. She disagrees: "Even though the starting point of our era may not correspond to the chronologist's intention, it is still the point from which we count our centuries - each of which still requires 100 years for completion."

Looking at newspapers of a century ago, one can conclude that our ancestors finally got things worked out.

The New York Times of Jan. 1, 1901, led with this headline: "Twentieth Century's Triumphant Entry." The Times described a huge midnight ceremony at City Hall: "Just as the hands of the big clock on the City Hall were on the point of marking the midnight hour, the lights outside were turned off. For an instant the outlines of the building were dark against the lighted background, then almost immediately the entire front burst into a flood of light. Every electric bulb was re-illumined, and the red, white and blue globes lit up the building in midday brilliance. [An electric sign] ‘Welcome Twentieth Century' stood forth again in striking prominence... ."

In Philadelphia, the Inquirer of Jan. 1, 1900, published a three-column cartoon on the front page showing a man in a dunce cap putting up a "20th century" sign only to be told by Earth, riding a bicycle: "That doesn't go up until I finish the last lap of the old century." On Jan. 1, 1901, the Inquirer proclaimed in a two-line streamer, "Hail, Twentieth Century! Farewell the Old and a Happy New Year to One and All." As in New York, the century was greeted with a display of lights at City Hall. "From nightfall until 1 o'clock the crowds thronged and surged about the streets," the Inquirer reported.

It had not been easy getting to that point. Confusion was so widespread that in Germany, the Kaiser had ordered a national celebration of the 20th century's arrival on Jan. 1, 1900. The New York Times rebuked him: "We think the Kaiser has made a very stupid mistake about a very simple matter."

The Washington Post's editorial page had waged a running battle with writers of letters to the editor contending that the century began on Jan. 1, 1900. The Post grew testy in an editorial: "If anyone will show us how a century can be completed with less than 100 years, and how nineteen centuries can be completed with less than 1,900 years, and how the twentieth century can begin before the nineteenth century ends, we shall joyfully put ashes in our hair and hail him as a wizard."

Ruth Freitag laments that a problem here is the shortness of human life. Although things eventually got sorted out a century ago, no one involved in that debate is around to deal with the new one. So we are destined to argue the point all over again.

In the next few years each of our newspapers will have a choice to make: go with the flow, or report the facts.

Editors should expect to hear arguments for taking the easy way out. The most common rationale I've heard for accepting Jan. 1, 2000, is that "everybody else thinks that is right; why should we be out of step with the world?" Newspapers that accept that reasoning would, if they were published in the 15th century, he obliged to report that the Earth is flat.

I don't see any alternative here. Journalism is, after all, dedicated to truth and precision. Besides, there are some readers out there who know better, and they're not likely to buy the flat-Earth argument.

Still, I would argue that once we've decided we will tell our readers the truth, we shouldn't be an obnoxious know-it-all. Assistant Managing Editor Allan M. Siegal of the New York Times refers to "the tide of public opinion" and counsels, "We shouldn't be stuffy about this." The Times, Siegal says, knows when the century starts "and when we write about it in a serious way, we will state the facts."

Lest the confusion continue in our own newsrooms, I think editors should decide, right now, to give their staffs some practical guidance. Here is how we've done it at the Inquirer:

"It is usually unnecessary, even undesirable, to correct people quoted in the paper as saying that the new century and millennium begin in 2000... .

"The Inquirer will not, however, contribute to the misinformation. Thus our writers will not state, explicitly or implicitly, that the new century and millennium begin in 2000... .

"Any story in the Inquirer that discusses the beginning of the new century and millennium will have a paragraph that states the facts. This will be done in a straightforward manner, neither scolding readers who think otherwise nor attributing the assertion (as has happened) to ‘diehard scholars' or ‘sticklers.' "

Finally, this is how the matter affects ASNE's own bridge to the 21st century:

If the current ladder of succession holds, the honor of presiding over the first ASNE convention of the new century and new millennium will go to Rich Oppel, at the J.W. Marriott Hotel in Washington on April 3-6, 2001. Oppel is scheduled to assume office at the end of the 2000 convention in Washington, so his administration, like Bill Clinton's, will begin in the 20th century and end in the 21st.

Foreman, chair of the Human Resources Committee, is deputy editor of the Philadelphia Inquirer.

Jennifer Ewing-Elliott of the Inquirer's news research library and sports editor Nancy Cooney helped in the preparation of this article.