When Queen Victoria donned a white satin dress for her 1840 wedding, it was viewed with some surprise. Wedding dresses could be any color, but white was neither fashionable nor common.
In truth, she'd picked it because she had a lovely 'deep flounce of Honiton lace' that she wanted to show off. That was white, so her dress was white; thus she sparked a 'custom' in fundamentally imitation brides, which has so far lasted nearly two centuries.
Royal wedding columnists had to find something to say about Victoria's white dress, and 'it matches her lace' wasn't going to cut it.
Without much in the way of meaning at all, they nicked the symbolic attributes of a truly ancient wedding dress color - blue. Thus pulling off a sleight of hand about 'purity' and 'piety' still erroneously repeated today.
Break free of Victorian misinformation! Return to your roots, wear an age-old hue that even your pre-19th century forebears would recognize as customary. Buy a blue wedding dress for your traditional walk down the aisle.