Morganatic marriage, sometimes called a left-handed marriage, is a marriage between people of unequal social rank, which in the context of royalty prevents the passage of the husband's titles and privileges to the wife and any children born of the marriage.
Generally, this is a marriage between a man of high birth (such as from a reigning, deposed or mediatised dynasty) and a woman of lesser status (such as a daughter of a low-ranked noble family or a commoner). Usually, neither the bride nor any children of the marriage have a claim on the bridegroom's succession rights, titles, precedence, or entailed property. The children are considered legitimate for all other purposes and the prohibition against bigamy applies. In some countries, a woman could also marry a man of lower rank morganatically.
After World War I the heads of both ruling and formerly reigning dynasties initially continued the practice of rejecting dynastic titles and/or rights for descendants of "morganatic" unions, but gradually allowed them, sometimes retroactively, effectively de-morganatizing the wives and children. This was accommodated by Perthes'Almanach de Gotha (which categorised princely families by rank until it ceased publication after 1944) by inserting the offspring of such marriages in a third section of the almanac under entries denoted by a symbol (a dot within a circle) that "signifies some princely houses which, possessing no specific princely patent, have passed from the first part, A, or from the second part into the third part in virtue of special agreements." The Fürstliche Häuser ("Princely Houses") series of the Genealogisches Handbuch des Adels ("Genealogical Manual of the Nobility") has followed this lead, likewise enrolling some issue of unapproved marriages in its third section, "III B", with a similar explanation: "Families in this section, although verified, received no specific decree, but have been included by special agreement in the 1st and 2nd sections".
Variations of morganatic marriage were also practised by non-European dynasties, such as the Royal Family of Thailand, the polygamous Mongols as to their non-principal wives, and other families of Africa and Asia.
Morganatic, already in use in English by 1727 (according to the Oxford English Dictionary), is derived from the medieval Latinmorganaticus from the Late Latin phrase matrimonium ad morganaticam and refers to the gift given by the groom to the bride on the morning after the wedding, the morning gift, i.e., dower. The Latin term, applied to a Germanic custom, was adopted from the Old High German term *morgangeba (modern German Morgengabe), corresponding to Early English morgengifu. The literal meaning is explained in a 16th-century passage quoted by Du Cange as, "a marriage by which the wife and the children that may be born are entitled to no share in the husband's possessions beyond the 'morning-gift'".
The morning gift has been a customary property arrangement for marriage found first in early medieval German cultures (such as the Lombards) and also among ancient Germanic tribes, and the church drove its adoption into other countries in order to improve the wife's security by this additional benefit. The bride received property from the bridegroom's clan. It was intended to ensure her livelihood in widowhood, and it was to be kept separate as the wife's discrete possession. However, when a marriage contract is made wherein the bride and the children of the marriage will not receive anything else (other than the dower) from the bridegroom or from his inheritance or clan, that sort of marriage was dubbed as "marriage with only the dower and no other inheritance", i.e., matrimonium morganaticum.