Britain is a place that is rife with traditions and legends, so it is little wonder that the tradition of the white wedding dress was started by the English Monarchy. Getting married in a white, extravagant gown was a sign that you could afford to buy a dress that you would never be able to wear again because of its style and colour (whites were not easy to clean in those days as they are today!).
Of course, women still continued to be married in various colours and styles of dress -- it was only the vain and the wealthy that insisted on white to follow in the footsteps of the wealthy Monarch. However, during Edwardian times, the white wedding dress once more soared to new heights of popularity, as Coco Chanel unveiled its new knee-length white wedding dress, complete with extravagant train.
Even so, with the depression that followed World War I and the approach of World War II, many women continued to make do with whatever type of dress they could afford, and this went on for decades. However, since simply wearing a white wedding gown can no longer mark their stature due to the availability of the white wedding dress, they now do this by infusing the dress with the most expensive silks, pearls and material possible, making it worth a king's ransom by the time it is finished.
Luckily, we don't all have to pay a fortune to look stunning for our wedding day, and there is now so much choice in colour, style, material and design that we can get married looking just the way we want -- and without having to sell all of our worldly possessions to do so!
The Internet is a great source for wedding dresses.