Her marriage to the Duke of Marlborough
(From the book Consuelo and Alva Vanderbilt: "The bride was 20 minutes late to her own wedding. It was noon of Nov. 6, 1895, the hour set for the marriage of one of America's wealthiest heiresses, Consuelo Vanderbilt, to the ninth Duke of Marlborough (le tout New York in attendance, Walter Damrosch's 60-man orchestra completing their Wagner and Tchaikovsky, platoons of policemen keeping hordes of curious citizens out of St. Thomas Episcopal Church). But the bride, greatly infatuated with an American socialite, was still at home, weeping uncontrollably in the arms of her father, William K. Vanderbilt, pleading with him to rescue her from a marriage enforced against her will by her notoriously dominating mother, Alva. As much as "William K.," grandson of Commodore Vanderbilt and heir to much of his fortune, had come to dislike his former wife, he managed to calm his pale, willowy 18-year-old daughter and led her to the altar. So after a long, wretched honeymoon, Consuelo, Duchess of Marlborough, assumed her duties as mistress of the 170-room Blenheim Palace, soon becoming the leading beauty of the Edwardian Age and, less predictably, one of its most committed philanthropists.")
And as a paper doll bride:
And you could also buy her peeress robes: