I had always thought that the tradition of a white wedding dress was to show that the bride is a virgin. But that is not the case at all, it's so much more interesting than that. It's credited to starting in 1840 by Queen Victoria who wed in a white court dress at her wedding to Prince Albertin in 1840. European and American brides had been wearing a plethora of colours, including blue, yellow, and practical colours like black, brown, or gray. As accounts of Victoria's wedding spread across the Atlantic and throughout Europe, elites followed her lead.
Debutantes had long been required to wear white court dresses for their first presentation at court, at a "Drawing Room" where they were introduced to the queen for the first time.
Worldwide, the color white has been associated with weddings and other significant life or spiritual events for millennia. In ancient Greek, white was the color of bridal joy, and brides not only wore white dresses and white flowers, but they also painted their bodies white.
In China, it was the color of purity and perfection, and thus uniquely suitable as a color associated with death, which they saw as the time when the deceased person moved towards ultimate perfection.
In ancient Japan, white was also the color of purity and innocence.
In Africa, the color white is associated with deities and worship.
In the Christian tradition, white clothes were worn at the time of baptism to represent spiritual purity and the washing away of sins.
Because of the limitations of laundering techniques before the later part of the 20th century, white dresses provided an opportunity for conspicuous consumption. They were favored primarily as a way to show the world that the bride's family was so wealthy and so firmly part of the leisure class that the bride would choose an elaborate dress that could be ruined by any sort of work or spill.
Although women were required to wear veils in many churches through at least the 19th century, the resurgence of the wedding veil as a symbol of the bride, and its use even when not required by the bride's religion, coincided with societal emphasis on women being modest and well-behaved.
Etiquette books then began to turn the practice into a tradition and the white gown soon became a popular symbol of status that also carried "a connotation of innocence and sexual purity."
 The story put out about the wedding veil was that decorous brides were naturally too timid to show their faces in public until they were married.
By the end of the 19th century the white dress was the garment of choice for elite brides on both sides of the Atlantic. However, middle-class British and American brides did not adopt the trend fully until after World War II.
With increased prosperity in the 20th century, the tradition also grew to include the practice of wearing the dress only once. As historian Vicky Howard writes, "[i]f a bride wore white in the nineteenth century, it was acceptable and likely that she wore her gown again". Even Queen Victoria had her famous lace wedding dress re-styled for later use.
The portrayal of weddings in Hollywood movies, particularly immediately after World War II, helped crystallize and homogenize the white wedding into a normative form.
The white wedding style was given another significant boost in 1981, when three-quarter billion people—one out of six people around the globe—watched Charles, Prince of Walesmarry Diana Spencer in her elaborate white taffeta dress with a 25-foot-long train. This wedding is generally considered the most influential white wedding of the 20th century.