THERE'S A LITTLE BIT of England tucked away among the imposing Gothic arches of Washington Cathedral. It is Chaucer's England, the England of Richard II and Henry V, of the Black Prince and the Wars of the Roses, of jousting knights and fair ladies. This is before chivalry died and way before women's lib: In this England, it was not possible for a woman to commission her portrait in brass.

You can learn a lot about medieval England -- customs, dress, armor, trades, professions, family stories, even ancestry -- and take home a decorative wallhanging for your room by visiting the London Brass Rubbing Center.

The day I stopped in, the aptly named manager, Ann Etches, was giving a lively talk on English church brasses to 28 youngsters from Washington's Sacred Heart School.

"Today, when you want to have yr image made, you use a camera. Well, in England between 1280 and 1650, it was the height of fashion for the upper middle class to have one's picture made in brass," she told them.

Brasses are flat pieces of metal engraved with the figures of knights and other notables of the time. They were set into stone slabs in parish churches -- some on table tombs, some on the walls or floor -- as memorials. Originally they were made from latten or "cullen plate," a mixture of zinc and copper invented in Cologne, Germany.

"You can decide when people lived from the clothes they are wearing," said Etches. The children, dressed in parochial school uniforms of light blue shirts, plaid skirts or dark trousers, focused their attention on a large brass of Sir Robert de Bures (a replica, as are all the brasses in the center).

The 1310 de Bures is considered "the finest military brass in existence," the only undamaged example of its time and type, said Etches. It shows a soldier of Edward I in chain mail, which tells us that he lived in the 13th century. Later knights, such as Sir William Fitzralph, wear plate armor.

Etches went on, pointing out other clues to de Bures' identity: His shield is dotted with ermine tails, which look like thistles or burrs; his legs are crossed, which means that he was a Crusader; he has a lion at his feet to show he was courageous.

Symbols had great significance in art from the Middle Ages. A dog with crossed legs meant loyalty to God; a dog with straight legs meant loyalty to king and country. Hands held together were a sign of respectability or religion; hands holding hearts in a dual portrait denoted love for one another.

The higher the hat, the wealthier the wearer. Ladies were not permitted to show their hair in public, so most wore headdresses or wigs. Etches used Margaret Peyton (1484) to illustrate. Margaret is wearing the popular butterfly headdress with gauze stretched over a wire framework and requiring a plucked hairline. "She was known as the lace lady and is the most famous female brass," explained Etches.

Brass rubbing was started by Oxford historians just before the turn of the century. There are about 4,000 brasses left in England out of an original 10,000. In the 1600s, when Puritans controlled the state church, Oliver Cromwell had them melted down for weapons.

Brass rubbing centers have developed in the last ten years or so, both as a conservation measure -- to save wear and tear on the originals -- and to help maintain historic churches in England. The London Brass Rubbing Center pays royalties to the churches that have the originals. (Of the center's 80 facsimile brasses, all but nine -- a madonna from Belgium and eight zodiac works made from Middle Ages German woodcuts -- are from medieval England.)

After the history lesson, Etches demonstrated how to make a brass rubbing on black rag paper with beeswax crayons. First, she wrapped a cloth around one finger and pressed the edge of the brass to find its outline. This creases the image. Next comes "planing," skimming the edge with the flattest, narrowest part of your wax. Then "coloring," achieved by lifting the wax to its end and rubbing up and down, "short, hard and fast for all you're worth," said Etches. Then "polishing," using a flat cloth to remove the creases and leave a shine. And finally, inserting a card under the paper to erase any mistakes.

Now it was the class's turn to have a go. With baroque background music to set the mood, they browsed among knights and ladies, merchants and kings, coats of arms, lions, unicorns, elephants and firebreathing dragons, choosing a brass to rub. In half an hour, their efforts were rewarded, as here a silver suit of armor, there a gold brocade dress came up on the blank sheets of paper.

Dionne Reeder, 13, rubbed hard on a madonna and child destined for her mother's room. Sisters Tara and Chanitta Perry picked their strological signs, Libra and Aries, for their bedroom. Douglas Martin had other plans for his rubbing of Cancer and Leo. "I'm putting mine in the bathroom," he cracked. "That's where everybody goes."

BRASS FACTS -- The London Brass Rubbing Center is in the gift shop crypt on the south side of the Washington Cathedral, Massachusetts and Wisconsin avenues NW. It's open seven days a week from 9:30 to 5. Admission is free. The cost of rubbings, $1.75 to $20 depending on which brass you choose, includes all materials and instruction. Large groups (more than eight) and class field trips should reserve by calling 364-9303. The charge is $3.75 per student and includes the talk.

There's a small gift shop in the center that has books and puzzles on heraldry, raised pictures of jousting knights and brass-rubbing kits, which make good gifts. The small kit is $3.25; the large kit is $15 and contains all you need to make 30 rubbings.