The White Wedding dress
Brides started wearing white in the 1840's, before that they wore silver or a color.
Something old, new, borrowed and blue
something old is for continuity
new is for optimism for the future
borrowed is for happiness
blue is for fidelity, good fortune and love
Diamond Engagement Rings
Have been around since 1477 but didn't become popular until the 1940's.
Invitations were delivered by a messenger on horseback so thus the purpose of an outer envelope. It would often get dirty and damaged en route and be discarded by the butler before the invitation was delivered to the recipient making the inner envelope the formal one.
The bouquet toss
In medieval weddings guests would tear off and take a piece of the bride's dress for good luck. To distract them from the gown brides started throwing their flowers.
Before a Turkish bride walks down the aisle, her single bridesmaids and relatives sign the soles of her shoes. After a night of dancing the signature that's faded the most will predict the next person to marry.
In Italy they give Jordan Almonds as favors. They are grouped in 5, representing health, wealth, fertility, happiness and longevity.