The Oxford University Press may be 500 years old but it doesn't wantonly abandon traditions, as one of its directors, Lord Blake, remarked yesterday. So it had a cake at its birthday party.

It is too bad for bakers and candlestick-makers that quincentennials do not come around more often. Oxford's cake had 501 candles on a three-and-a-half-food-square confectionary model of the press' building in Oxford.

They had to turn off all the sprinklers and alarm systems in the Pierpont Morgan library so that guests could stay dry and the fire department unperturbed while the candles blazed in honor of 500 years of distinguished publishing history that began when Theodoric Rood (The Red) moved to Oxford from Cologne and ran off his first book.

The best-known misprint in Oxford's history came in Theodoric's first book. An "X" was dropped from the Roman numeral date, and the 1478 commentary of the Apostle's Creed appears to have been printed 10 years earlier.

Only 17 books printed by Theodoric at Oxford are known. In its quincentennial year, Oxford University Press will publish 800 new books. The press keeps about 19,000 books and items of music in print.

Oxford employs about 3,000 in Britain and 23 other countries, and last year made a pretax profit of $12.5 million on sales of about $88 million.

While other publishers make big profits from the memoirs of fallen public figures and novels about fallen and about-to-be-fallen women, Oxford has relied on the Bible for its bread and butter.

Not all Oxford's Bibles have sold a million copies the first day they appeared, but the New Testament of the Revised Standard Version did. When Oxford opened its first overseas branch in New York in 1896 its purpose was to distribute Bibles.

Its first book published in America was an annotated edition of the King James Bible, the Scofield Reference Bible of 1909, which is still heavily used in the U.S. Evangelical Christian movement.

Oxford's other best sellers include Robert Burton's "Anatomy of Mclancholy" and Peter Heylin's "Microcosmus" of 1621, and such 20th century books as Rachel Carson's "The Sea Around Us" (1951), Edmund Wilson's "The Scrolls From the Dead Sea" (1955) and, of course, the Oxford English Dictionary.

The driving force behind the project was Sir James Murray, a self-taught Scottish schoolteacher who was 42 when he was commissioned the dictionary's editor.

Murray read 25 languages and had a passionate interest in geology and botany, but his greatest interest was in learning.

"I employed all my leisure time . . . in learning as far as I could something about everything that I did not know, while also trying to learn everything that could be known about some things," Murray wrote to one of his 11 children. "I was always . . . sharpening my mental and intellectual tools in the faith that they would be useful."

Murray died shortly after completing the "Trink-Turndown" volume in July 1915. The last of the 12 volumes containing the dictionary's 414,825 definitions illustrated by 1,827,306 quotations was published in 1928.

The Oxford University Press enters its quincentennial year with 17 English and 40 foreign dictionaries in its catalogue. A court has ruled that no other publisher can use the word Oxford in a dictionary title.

It was not until William Laud, archbishop of Canterbury and chancellor of the university, turned his attention to the press that it was given royal charters in the 1630s giving it the legal right to print.

Laud was followed after the Reformation by the bishop of Oxford, John Fell, whose enormous contributions to learning are less well known than the doggerel:

"I do not love thee, Doctor Fell/The reason why I cannot tell . . . " which was written by a student who, like many, found Fell a difficult man.

Fell published 150 books at Oxford, imported elegant types from Holland and secured the press its arrangement for printing Bibles that has proved so rewarding.

Oxford University Press owns 550 different fonts of type, including hieroglyphics and Minoan characters.

On Sept. 7, as part of its quincentennial, Oxford will open an exhibition at the Library of Congress on learning and language. Oxford officials hope to have an oral system in operation so that visitors to the exhibition can look at the samples of rare and ancient languages and hear them pronounced and translated.

The exhibit that opened yesterday with the cutting of the giant cake was assembled by Nicholas Barker and is called "The Oxford University Press and the Spread of Learning."

Among its 332 items are Theodoric's first book, the 1612 map and account of the colony of Virginia by Capt. John Smith. "Alice's Adventures in Wonderland" (1865), examples of typefaces and portraits of people important in the history of the press. It includes an autographed photograph of Abraham Lincoln, who was one of the 10 American presidents believed to have owned an Oxford Bible.

Henry Geldzahler, New York's cultural affairs commissioner, welcomed the exhibition and praised "the enduring standards and qualities" of the Oxford University Press.

Then he join Lord Blake, George Richardson, the press's chief executive, and the head of its New York branch, Byron Hollinshead, in blowing out 501 candles.