Carrying Over the Threshold
Why does the husband traditionally carry his new wife over the threshold of thir home the first time they enter it as a married couple? Where did the custom originate? There seem to be two main theories.
Property
One possibility is that the tradition dates back to when the woman was considered in effect the property of her husband; in fact in some cases she would have been literally stolen away from her family. By carrying her in the man was asserting his "ownership" of her.
Luck
A more appealing explanation concerns luck. Evil spirits were said to wait for the newlyweds in their home. When they entered, the spirits would try to trip them up. Tripping and falling as you crossed the threshold was a sign that the spirits had taken possession of the house and back luck would follow. The man thus carried the woman over the threshold to reduce the chance of her stumbling.
This explanation has a certain romantic appeal but really doesn't make a lot of sense; a man carrying a woman is far more likely to trip than the two
entering individually!