In times of old, brides were often not courted into marriage but instead they were captured during neighboring wars. In these times, the duties of what we have come to know as the best man and the groomsmen were to protect the groom from the fury of those he had previously captured his future bride from. They were ready to give up their lives to ensure the safety of the groom.
The custom of the bride standing to the left of the groom during the wedding arose from a need rather than etiquette. During the ceremony the groom needed to have his right arm free to defend against any intruders who may have attempted to reclaim his future bride before the conclusion of the ceremony.
In ancient times the bridesmaids had a more ominous duty. They were dressed in identical clothing. This was done in the hope of confusing the evil spiritis that may be decending on the bride. The bridesmaids were ready to absorb any evil spirits that may have been ready to attack the bride.