It seems that this tradition about wedding is from Great Britain. But nowadays, every bride knows it in Europe. This European tradition about wedding deals with the bride. The bride has to wear something old, someting new, something with blue and something that she borrowed.
This tradition about wedding is symbolic. The bride wears something old to be linked with her family and her life before wedding. Usually it’s a jewel. The new item is to have chance for this new life. Often, brides decide to wear a new wedding dress. Next, the bride has to borrow something to another bride, who has been lucky with her wedding.
The blue item represents faithfullness.