When is George Washington's real birthday? Tomorrow? Last Tuesday? Or is it next Saturday?

History plays tricks on us, and Congress moves holidays. But at least in the nation's home -- the White House -- there has always been another Father's Day. More precisely, it was Father's birthday. The day was the 22nd of February, and the man was George Washington.

These days, his actual date of birth is completely confused, what with the very government he helped to establish fudging it so government workers will have a three-day weekend (that was made into law in June 1968 and put into practice in 1971). But even the icon himself had trouble.

Washington was the first of four presidents born under the Julian calendar (the "old style"), which was the standard calendar for England and its colonies. By its count, he was born on Feb. 11, 1731.

In 1752, the Julian was replaced by the Gregorian (the "new style"). In the Julian, the first day of the year was March 25, but in 1751 the year was ended on Dec. 31. So George Washington was 19 years old on Feb. 11, 1750, but turned 20 on Feb. 11, 1752, not 1751.

And to complicate it further, since the vernal equinox had displaced 11 days in the old calendar, the difference was removed by the omission of 11 days starting from September 1752 -- the day after Sept. 2 was Sept. 14. This meant that 11 days had to be compensated for, and in 1753 George Washington's birthday officially became Feb. 22. Privately, however, he continued to celebrate it on the 11th. Even though it really wasn't his birthday, it was.

Even Martha Washington had her birthday troubles, not knowing her actual birthdate -- June 13 or June 21, 1731. Either day she turns out older than George. Even though she was born after he was.

By the time Washington became president, his birthday was generally acknowledged to be Feb. 22. And when the day rolled around for the first time during the first year of the first president, it appeared that yet another royal custom eschewed by the goodly democratic colonists during the war being revamped for their new ruler, the president of the United States.

As it remains in Great Britain, the birthday of the king or queen was a day of national celebration -- the people's holiday to honor their ruler (even though in England the queen's "official birthday" is not the same day as her real birthday). So it was on Feb. 22, 1790, that President Washington's birthday was first celebrated by the New York public at the Presidential Mansion on Cherry Street in New York City (the first capital of the United States). Washington's birthday was celebrated every year during his administration.

His 1796 birthday celebration was unprecedented. At dawn, there was a cannon salute and peal of the bells in Philadelphia (the second capital was established there), and the public came in a steady stream during the afternoon to the Presidential Mansion, where they had punch and cake. That night a grand ball was held, and all the women wore white.

Washington's last birthday celebration as president was overwhelming. It came two weeks before the first first family's final departure for Mount Vernon. The ball was held in Philadelphia's Rickett's Amphitheater; as 12,000 guests headed for their dinner tables, "There was danger of beingsqueezed to death." A band played the new tune that had been written for the special day, a line of which ran, "Come, boys, close the windows and make a good fire . . . 'Tis the day that gave birth to our country's bless'd sure . . ." The president put up no protest.

Oct. 30 (or Oct. 19th in the "old style") was not celebrated by the masses. That was the birthday of the second president, John Adams.

Adams had, by this time, just about enough of the deification of his predecessor, to whom he always took second place, even at his own Inauguration Day. Adams refused to attend the Washington birthday celebration of 1798, disapproving of the annual event as unsuitable for a democracy where all men (and presumably to Adams, all presidents) were equal. He considered it dangerously monarchical. Adams' wife Abigail recalled that the fall of the Roman Empire had been helped by the glorification of military heroes, so when some prominent Philadelphians sent him an invitation the president simply wrote a curt "Declined" across it.

Abigail Adams was logical about it, "How could the president appear at their ball and assembly but in a secondary character . . . to be held up in that light by all foreign nations?"

The rejection touched off a political controversy. Federalists, already factionalized, took it as an insult to the party. For Thomas Jefferson, the democrat, it was wonderful. "The late birthnight has certainly sown tears among the executive Federalists," he wrote to a fellow Virginian. Many of those who had subscribed to a ticket were so let down by the Adams' rejection that they didn't show up either.

But Washington's birthday was observed in one form or another by succeeding presidents. At Andrew Jackson's 1837 party, the general public was invited to visit the frail outgoing president, who sat in a chair for several hours in the Blue Room, while his hostess Sarah Yorke Jackson did the handshaking duties along with the vice president, who was also the president-elect, Martin Van Buren.

The day's main focus, however, was a huge cheese, which had been sent to Jackson and which the public gladly stabbed into. The halls reeked for weeks after. There is no record of Van Buren holding a Washington's Birthday open house.

During John Tyler's administration, a private masquerade ball was held on Feb. 22, 1843, at which the widowed president continued his passionate pursuit of his future wife, Julia Gardiner. Julia was dancing with a beau, but immediately after the band finished the polka, Tyler boldly came up to the couple. "I must claim Miss Gardiner's company for a while," he explained, taking her for a promenade during which he proposed. "I had never thought of love," Julia Tyler later claimed, "so I said, 'No, no, no' and shook my head with each word, which flung the tassel of my Greek cap into his face with every move. It was undignified, but it amused me very much to see his expression as he tried to make love to me and the tassel brushed his face."

Perhaps knowing a good thing when he saw it, Franklin Roosevelt began celebrating a different presidential birthday -- his own. Beginning in 1934, FDR held birthday balls each Jan. 30 to raise funds for the Georgia Warm Springs Foundation. At one party, women friends and family members gathered around him dressed as a god, olive-leaf crown and all.

Other presidents' birthdays have been used for political purposes. Once the Republicans began celebrating at "Lincoln Day" testimonials in the '20s during the Coolidge administration, the Democrats retaliated with "Jefferson-Jackson Day" dinners. But no president's birthday parties have come close to those of Father George.

In modern times, the most interesting White House celebration of Washington's birthday was organized by Pat Nixon, who began a special series of varied American entertainments called "Evenings at the White House." On Feb. 22, 1970, she hosted an "evening" with a full-length performance of "1776," the then-popular Broadway musical.

Curiously, though George Washington is regularly referred to in the play, he never appears as a character. Perhaps it was a rather posthumous and backhanded remembrance -- on Numero Uno's birthday at that. The star of the show was John Adams.