Royal Intermarriage

Royal intermarriage is the practice of members of ruling dynasties marrying into other reigning families. It was more commonly done in the past as part of strategic diplomacy for reasons of state. Although sometimes enforced by legal requirement on persons of royal birth, more often it has been a matter of political policy and/or tradition in monarchies.

From the medieval era until the fall of Napoleon I most European heads of state were hereditary monarchs in pursuit of national and international aggrandisement on behalf of themselves and their dynasties. Thus bonds of kinship tended to promote or restrain aggression. Marriage between dynasties could serve to initiate, re-enforce or guarantee peace between nations. Alternatively, kinship by marriage could secure an alliance between two dynasties which sought to reduce the sense of threat from or to initiate aggression against the realm of a third dynasty. It could also enhance the prospect of territorial acquisition for a dynasty by procuring legal claim to a foreign throne, or portions of its realm (e.g. colonies), through inheritance from an heiress whenever a monarch failed to leave an undisputed male heir.

Also following Europe's medieval era when tribal leaders evolved into feudal suzerains, suzerains into kings and kings into absolute monarchs, they rose from primus inter pares into God's anointed sovereigns. Marriages with subjects brought the king back down to the level of those he ruled, often stimulating the ambition of his consort's family and evoking jealousy—or disdain—from the nobility. The notion that monarchs should marry into the dynasties of other monarchs to end or prevent war was, at first, a policy driven by pragmatism. During the era of absolutism, it came to re-enforce the notion of Divine right—i.e., the premise that monarchs and dynasties were chosen to reign by God and, ipso facto, were different, as if by caste, rather than merely by fortune from their subjects. Kings continued to marry into the families of their greatest vassals down to the 16th century in most of Europe, by which time most of the great regional principalities and duchies were annexed to the Crown in Scandinavia, Latin Europe and the British Isles through royal subjugation or inheritance. Henceforth, kings tended to marry internationally and, increasingly, to have their sons and daughters do likewise.