New Delhi, April 11 -- The late Queen Elizabeth II believed the monarch had to be seen to be believed. And she made sure that was true even when Britain's famously changeable weather intervened, pioneering the use of a clear plastic raincoat so that a stodgy black umbrella didn't obscure her from public view.

That raincoat is one of some 300 garments and other fashion artifacts that go on display Friday at the King's Gallery at Buckingham Palace in an exhibit that celebrates the late queen's life and reign as Britain prepares to mark the centenary of her birth. The most comprehensive exhibition of her style choices ever mounted, the show charts Elizabeth's story, and her impact on British fashion.

"I think she had a definite sense of wh...