A wedding breakfast is a dinner given to the bride, bridegroom and guests at the wedding reception that follows a wedding in the United Kingdom, Germany, Austria, Scandinavia and some other English-speaking countries. The Compact Oxford Dictionary[1] lists the phrase as only “British”, and the Merriam-Webster online dictionary[2] does not list it at all.
The wedding breakfast is not normally a morning meal, so its name is puzzling. The name is claimed[3] to have arisen from the fact that in pre-Reformation times the wedding service was a Mass and the bride and bridegroom would therefore have been fasting before the wedding; after the ceremony the priest would bless and distribute some wine, cakes, and sweetmeats, which were then handed round to the company. Since in the old Catholic custom no-one may take Mass unless they have fasted since daybreak, this was literally a “break fast” for the bride and groom, though others in attendance would not necessarily take communion and therefore would not necessarily have been fasting. The author of Party-giving on Every Scale (London, n.d. [1880]) reported a more direct origin:
The orthodox "Wedding Breakfast" might more properly be termed a "Wedding Luncheon," as it assumes the character of that meal to a great extent; in any case it bears little relation to the breakfast of that day, although the title of breakfast is still applied to it, out of compliment to tradition. As recently as fifty years ago luncheon was not a recognized meal, even in the wealthiest families, and the marriage feast was modernized into the wedding breakfast, which appellation this entertainment still bears.
The Oxford English Dictionary does not record any occurrences of the phrase "wedding breakfast" before 1850, but Queen Mary and Philip of Spain are known to have had their wedding breakfast at the East Hall of Wolvesey Castle on 25 July, 1554. So this custom, like the Christmas tree, may have been popularized in Britain or reimported from Germany during the Victorian period, because of Queen Victoria's German husband, Prince Albert.