Egregoros

@rosey my understanding is in less civil times, weddings were risky business so the groom selected the best swordsman he could find to defend his bride while he was busy with the ritual part of marriage. at the same time, if this guy was well-known as an honorable person, his willingness to serve this role reflected well on the groom's character.
as brides getting kidnapped during weddings became a rarer occurence, the best man role became ceremonial and more a matter of "who's ny best friend."