Queen Victoria

Before Queen Victoria's wedding to Prince Albert in 1840, brides typically wore their best dress on their big day, regardless of its color. Queen V's knockout white gown was so spectacular that brides began vying for similar styles, which is how the brides-in-white tradition began.
After Queen Victoria's consort, Prince Albert, died in 1861, she wore black everyday as a sign of mourning until her own death in 1901.