some traditions never die

but why carry over the threshold ?
As it turns out, weddings in the days of yore sometimes followed kidnappings. This explains not only the role of the best man but also why the bride and groom customarily leave the wedding celebration before everyone else. It's symbolic of the groom stealing away with his bride, whisking her from her family and into a new life with him. The kidnapping theme also explains why grooms carry their brides over the threshold in some cultures. In Medieval Europe, carrying a bride into her new home prevented her from seeming too enthusiastic about losing her virginity. By picking her up and taking her into their home, the groom provided an alibi for his wife's chastity