All those stories you've heard about the death of Washington society, and the disregard for etiquette are, to put it politely, not true.

As evidence, the Chronicler presents the proper and pleasant 90th birthday party last week for the last Mrs. Peter to preside at Tudor Place -- Helen Tucker (Mrs. Armistead) Peter.

Author Hope Ridings Miller, who has been to most Washington parties for more years than she'll reveal, looked around and said, "These days, how remarkable to go to a party this size and not have to buy a ticket!"

Not only was it not a benefit, it was not even corporately sponsored -- the trustees of Tudor Place Foundation picked up the tab for all those delectables everyone used to enjoy so much before cholesterol.

Instead of speeches, Austin H. Kiplinger, president of the trustees, gave a toast to the "love of Helen and her support for this beautiful place."

For years, Kiplinger revealed, Mrs. Peter, known on 31st Street as the "Monarch of the Glen" for her Scots bonnets and kilts, has fussed: "Queen Elizabeth II has a thistle pin, the dowager Queen has a thistle pin, but I do not have a thistle pin." So on behalf of the trustees, he gave her a thistle pin, the emblem of Scotland. Mrs. Peter pinned it on her dress, made from a sari Osborne Phinizy Mackie brought her from India. She was heard to say that she had it made with a train "because I never had a dress with a train after my first wedding."

Mrs. Peter, who was instrumental in preserving Woodlawn, the house of another Washington step-granddaughter, went to Scotland 50 times to learn from its national trust procedures for establishing the U.S. National Trust for Preservation. This summer, she and Mary, Countess of Strathmore, had tea with the Queen Mother, who is also 90 this year, at her log cabin at Balmoral.

About 350 or so grande dames and august gentlemen -- mostly card-carrying cave dwellers -- with a smattering of great-grandchildren and such gathered last Tuesday to drink champagne and eat cake (a huge one decorated with a facade of Tudor Place) on the glorious lawn of Tudor Place, carefully tended for almost 200 years on the gentle Georgetown hillside.

Invitations to the evening were from a drawing by James W. Glass from the Tudor Place Collection and bore the notation, "A party in Georgetown at Mrs. Peter's Tudor Place, 1840." Mackie noted the design was used because "it seemed appropriate to invite people to a party for the last Mrs. Peter of Tudor Place with a drawing of one for the first."

Across from the receiving line was a pasteboard figure, made from a picture of Mrs. Peter dressed as a black pearl in flowing black chiffon, a prize-winning costume at a Depression-era ball.

Most of the stories told that night were either about or by the vivacious Mrs. Peter, whose laugh, rather like a well-wound music box, tinkled through the party.

Mrs. Peter thought of a few the day before the party in the grand Victorian mansion where she lives now, the dower house bordering Tudor Place. The glorious brocade curtains made, it is said, in 1840, "I found in a box of my mother-in-law's. All they needed was to be relined."

When she married Armistead Peter III in 1973, he had already willed Tudor Place to the Trust. The Victorian house, built by a long-ago Beall of the family whose farm made up much of Georgetown, was reserved for her widowhood and her own family antiques and those she inherited in her two previous marriages, to the late Rear Adm. Atherton Macondray and Eliphalet Fraser Andrews.

Mrs. Peter remembered a kaleidoscope of Washington scenes from this century. During World War I, she and her Holton Arms classmates "wore middy blouses, pleated skirts and high stockings, and carried wooden rifles as we did a military drill, down Connecticut Avenue." During World War II she was a gray lady at the Naval Hospital. One of her famous exploits was when she was chairman of the Junior League Ball marking the closing of the Belasco Theater. "We had two men dressed as horses, and I was the rider." When she was a debutante, Garfinckel's gave her and the other young women each a feather fan.

This week, she seemed not a bubble less ebullient than she was half a century or more ago. In this she resembles those who also called Tudor Place home. Martha Custis Peter, George Washington's step-granddaughter, lived in her grand house designed by William Thornton for more than 50 years. Her daughter, Britannia Wellington Peter Kennon, died on the eve of her 96th birthday in 1911. And her great-grandson, Armistead Peter III, was 87 when he died in 1983.

Who would doubt that at Tudor Place, time stands still?