WHEN PRINCE CHARLES WAS INTRODUCED last June to Matthias Funck, son of the late co-inventor of Doc Martens shoes, His Royal Highness put the obvious question: "What makes Doc Martens so popular?" Funck, 49, was confounded. "I couldn't tell him," he says.

Indeed it is no mean task to explain why these prosaic clodhoppers should be regarded more as funk than as clunk. Yet they are worn on such famous and disparate feet as Diane Keaton's, Sinéad O'Connor's and the Dalai Lama's. In fact, Prince Charles himself has a pair. "Maybe it's a footwear version of Levi's," says Stephen Griggs, 31, president of R. Griggs & Co, the English firm that produces 160,000 pairs each week. Docs come in dozens of styles and colors, though it's the lace-up boot called 1460—for the April 1, 1960 date it first came plodding off the assembly line—that's most popular. Now selling for about $100 a pair, they became a menacing calling card for skinheads and punks in the '60s and '70s. Lesbians and gay men adopted them next, and the rest of the world followed feet first.

Docs were invented in 1946 by a German physician, Klaus Maertens, after he hurt his foot skiing. Seeking a comfortable convalescence, Maertens used truck lire to create a shoe with an air-pocket sole that would ease the pressure on his feet. His buddy, Dr. Herbert Funck, an engineer, helped perfect the design. In 1959 they licensed R. Griggs & Co. to manufacture the shoes, but Klaus's son, Max Maertens, 30, and Funck are still involved in marketing. Coming soon: a line of Doc Martens clothing. What next—cologne? Jokes Griggs: "It would have to smell of leather."