WHAT IS THE EQUAL MARRIAGE RULE? WHO INTERPRETS IT?
It was the Imperial House of Habsburg, rulers of the Holy Roman Empire and later of Austria-Hungary, which instituted a strict rule requiring dynasts to contract equal marriages. This meant that an archduke had to marry a royal princess in order to transmit dynastic status to his children. If he married a non-royal wife, even a wife from the high nobility, he was said to have contracted a non-dynastic marriage, and his children were not members of the dynasty. Non-dynastic marriages were also called morganatic or unequal marriages. As an example, the heir to the Austrian throne, Archduke Franz Ferdinand, married a non-royal wife. When he and his morganatic spouse were assassinated in Sarajevo in 1914, he was succeeded as heir to the throne not by his son (who was not a dynast), but by his nephew.
This equal marriage rule was also followed by the dynasties of other countries that were once part of the Holy Roman Empire or were once under the Habsburgs. By the 19th century, in addition to Austria, this included the dynasties of the Kingdoms of Prussia, Bavaria, Saxony, and Hanover, dozens of other sovereign states of the German Empire, and the Kingdom of Spain. Many formerly reigning German dynasties, such as the Prussian dynasty, still enforce the equal marriage rule today. Other dynasties have now dropped it.
For more than a century, from 1711 until 1820, every child, grandchild and great-grandchild of Peter the Great who chose to marry contracted an equal marriage with a dynast from a foreign royal house. By the reign of Emperor Alexander I (who himself was 1/8th Russian and 7/8th German by descent), the applicability of the Germanic equal marriage custom was well understood by all Russian dynasts, although it was not yet formal law. In 1820, however, Alexander I’s younger brother, Grand Duke Constantine, divorced his royal wife in order to marry his non-royal mistress. On the day the first marriage was officially annulled, Alexander I formally added to the dynastic laws the requirement that henceforth every Russian dynast was required to marry a royal spouse in order to pass dynastic status to the children of the marriage. He wanted to deny any children who might be born to Grand Duke Constantine’s second marriage from having dynastic rights. This rule has remained in effect until today.
The two marriages of Grand Duke Paul, a younger son of Emperor Alexander II, illustrate how the equal marriage rule worked in the Russian dynasty. His first wife was a princess of the Greek Royal House, and they had one son. That son was a dynast and a Grand Duke of Russia. Grand Duke Paul’s second wife was a commoner, and they had one son. That morganatic son was not a Russian dynast and thus, under Russian imperial law, did not even inherit the Romanoff surname. He was given a different surname (Paley) and a title that was noble, not royal.
When a dynasty has an equal marriage rule, it is always up to the head of the dynasty to determine whether a given marriage satisfies the rule. His decision is then binding on the dynasty. The dynastic head is also empowered to grant exceptions to the rule. For example, when one of the sons of German Emperor Wilhelm II married a commoner in 1914, he granted her the morganatic title of Countess von Ruppin. But while in exile in Holland after World War I, Wilhelm II granted an exception to the rule and recognized the children of the marriage and his daughter-in-law as Princes and Princesses of Prussia and Royal Highnesses. Similarly, when the son and heir of Crown Prince Rupprecht, head of the Bavarian royal dynasty, married a non-royal wife in 1930, Rupprecht considered it a morganatic union. In 1949, however, the Crown Prince amended the rule and recognized his grandchildren and his daughter-in-law as Princes and Princesses of Bavaria and Royal Highnesses. And in 1953, when his younger brother, Archduke Rudolf, married a non-royal Russian countess, Archduke Otto, head of the Austrian dynasty, allowed an exception to the rule and recognized the marriage as dynastic.
The head of a dynasty also has the right to abolish the equal marriage rule. Archduke Otto abandoned the rule for the Austrian dynasty at the time of the marriage of his son and heir to a commoner in 1993. The Duke of Bavaria abandoned it for the Bavarian dynasty in 1999. King Juan Carlos abolished it for the Spanish dynasty in connection with the 2004 marriage of the present king to a commoner.
No head of the Russian dynasty has ever granted “an exception” to the equal marriage rule. There were three instances, however, in which the Russian dynastic head had to interpret the equal marriage rule and determine that the marriage in question was an equal marriage. This was because Russian dynasts had invariably married royal spouses from the ancient Protestant reigning dynasties of northern Europe, or their offshoots (such as the Greek dynasty, founded by a Danish royal prince). The three marriages in question did not fit this northern European mold.
The first was the 1839 marriage of Grand Duchess Maria, the eldest daughter of Emperor Nicholas I, to Maximilien de Beauharnais, Duke of Leuchtenberg. Maximilien was the son of Eugène de Beauharnais, Napoleon Bonaparte’s stepson. Eugène was born a French nobleman (his father was a vicomte), but not a royal prince. After Bonaparte had made himself Napoleon I, Emperor of the French, in 1804, he formally adopted Eugène as his son and created him a Prince français, with the predicate of Imperial Highness. This new French dynasty then reigned only until 1814 before being initially deposed. How did the tsar view Maximilien, whose father was the adopted son of the head of a new dynasty that Russia had fought to overthrow? Nicholas I determined that Maximilien, through his father, was a dynast of a formerly reigning sovereign house (even though it had only reigned for a decade in the early 19th century), and he recognized the marriage as an equal marriage, so that the children of the marriage would be in the eventual line of succession to the Russian throne.
The second was a half century later: the 1889 marriage of Grand Duke Peter of Russia to Princess Militza of Montenegro. Militza was the daughter of reigning Prince Nicholas I of Montenegro, the monarch of a remote Balkan principality. This dynasty had only held secular sovereignty since 1851 and was not related by blood to any of the ancient dynasties of Europe. (Militza’s father did not promote himself to King of Montenegro until 1910). Emperor Alexander III approved the union as an equal marriage, on the basis that Militza was a princess of a sovereign house, even though it had been reigning less than 40 years. (At the same time, he also approved the marriage of her sister Anastasia of Montenegro to another member of the extended Imperial House: George, Duke of Leuchtenberg, a son of the 1839 marriage of Emperor Nicholas I’s daughter to Maximilien de Beauharnais.)
The third was the 1948 marriage of a Russian dynast to a princess of an old rather than a new royal dynasty: Grand Duke Wladimir (Head of the Imperial House from 1938 to 1992) to Princess Leonida Bagration. He deemed his to be an equal marriage, because the Bagrations were one of the oldest Christian dynasties of Europe, having ruled as kings in Georgia from the 9th century to the 19th century, far longer than the Romanoffs. The ancient Georgian Royal House of Bagration had many branches, three of which were reigning simultaneously as kings in the Caucasus in the 18th century. Therefore, the Bagrations did not pose the problem of being a new dynasty that had only reigned for a decade (like the Bonapartes) or for less than four decades (like the Montenegrins). The issue to analyze was the fact that the Romanoffs had deposed the two remaining Bagration kings early in the 19th century and absorbed their territories. Thereafter, the Russian tsars held several Bagration royal dynasts as prisoners in Russia and, after harshly suppressing uprisings in the Caucasus in favor of the restoration of the Bagration tsars, began to treat the Bagrations as mere subjects rather than as princes of the royal blood. Grand Duke Wladimir determined that, with both dynasties having been deposed, they were on an equal footing as formerly reigning royal houses.
 Under the monarchy, the Romanov name was limited to dynasts. Children of morganatic marriages contracted by male dynasts were non-dynasts and received different surnames, such as Yurievsky, Torby, Iskander, Paley and Brassov. After the monarchy fell, this usage ended, because non-dynastic children born abroad to dynasts inherited the Romanov surname of their fathers under the laws of countries such as Britain, France and the United States.
 In his capacity as dynastic head, Grand Duke Wladimir had in fact made this determination about the Bagrations two years before his own marriage. At the time of the 1946 marriage of a Bagration prince to a princess of the Spanish Royal House, the bride’s father, Infante Ferdinand of Spain, requested the Grand Duke’s view as to whether he would deem the marriage to be an equal one. In determining that, for equal marriage purposes, the Bagrations were the same as any other formerly reigning royal house, he was also mindful of righting an historical wrong. When in 1801 Emperor Alexander I overthrew Tsarevich David Bagration (Regent of Georgia following the death of his father, King George XII), he violated a solemn treaty entered into in 1783 by Catherine the Great, under which Russia undertook in perpetuity to safeguard the royal status of the Bagrations and keep them on the Georgian throne. See THE ROYAL HOUSE OF BAGRATION SOURCE MATERIALS on this website.