Cousin Marriages: The Zenith of High Dynasticity
It is natural to assume that the pressures of status equivalence and common religion increased the propensity for cousin marriages (Kuper 2009, 21). Although this is true, the explanation as such does not suffice, especially as it is known that the canons had defined marriages within seven degrees of consanguity as incestuous and therefore were strictly prohibited. The situation did not essentially change when the rule of con- sanguity was reduced to four degrees of kinship. In addition to consanguine marriages, affine marriages had been forbidden since the Middle Ages (Brundage 1990, 355-6, 435). In England under Cromwell, incest carried the death penalty, but there were only a handful of prosecutions and the death penalty was hardly ever actually imposed for incest (Kuper 2009, 55). In Sweden and hence in Finland, the situation was similar in the sixteenth and seventeenth centuries: the death penalty was in force but never executed (Aalto 1996, 96-7). In the seventeenth century England permitted marriages between cousins, but not between relatives- in-law (Kuper 2009, 63). The clergy were also often vehemently opposed to marriages with relations, because they were prohibited in the Bible
(Sundberg 2004, 28, 91; Rangstrom 2010, 146). However, as we will see in this book, dispensations to marry cousins, even first cousins and relatives-in-law, were granted quite readily. This clearly speaks for the significance of cousin marriages to sovereigns. Here (cf. Kuper 2009, 22), the category of cousin marriages includes not only marriages to first cousins, but also marriages to other closer relations, such as second cousins; first and second cousins once removed; nieces, nephews, uncles and aunts; and sisters- and brothers-in-law. Each cousin marriage is counted for both partners. So, when Louis XIV married his cousin Maria Theresa in 1660, the marriage is counted twice: first when computing the proportion of cousin marriages for monarchs, and second when computing the proportion of cousin marriages among monarchs’ siblings. In the case of in-laws, only those marriages that created in-law relations are counted as cousin marriages.
Royal genealogies show that in seven monarchies (Russia is excluded because of incomplete information about kinship) between 1500 and 1800, 44 per cent of monarchs married their relatives. The figure for Catholic monarchies is 50 per cent and for Protestant monarchies 39 per cent. The percentages were very high, particularly in Catholic monarchies (Austria 56 per cent, Spain 53 per cent and France 42 per cent). In the Protestant marriage market, the percentages were 47 for Prussia, 43 for England, 40 for Sweden and 20 for Denmark. These differences were in line with those seen in royal-to-royal marriages. Let us begin by looking more closely at the high occurrence of cousin marriages in Spain—an effort that is worthwhile despite the difficulty of following the names across several successive generations.
Due to Portugal’s colonial conquests, the Spanish monarchs regarded the Portuguese royal house as their equal in status and therefore as a suitable matrimonial partner. In 1498, Manuel I, King of Portugal, married Isabella, daughter of Isabella of Castile and Ferdinand of Aragon, the unifiers of Castile and Aragon. The said young Isabella was widow of the heir apparent of Portugal, Manuel’s brother. Thus, Isabella married her brother-in-law, but she was also Manuel’s first cousin. After Isabella’s premature death, Manuel I of Portugal once more married a Spanish princess, this time Isabella’s sister, Maria. He was thus married to his first cousin, who was also his sister-in-law. After the death of Maria, Manuel
I again turned to the Spanish monarch to marry her daughter Eleanor, a niece of Manuel’s two ex-wives. A whole series of cousin marriages was thus in full swing by the turn of the sixteenth century, bearing in mind that the parents of Isabella and Maria, the said Ferdinand and Isabella, were also relations. Cousin marriages continued in the next generation. In 1525 Manuel I’s successor, John III of Portugal, married Catherine of Spain, his first cousin, who was Queen Juana I’s youngest daughter. In 1526 King Charles I of Spain, who was Eleanor and Catherine’s brother, in turn married John III’s sister, Isabella of Portugal, his first cousin. In the third generation Charles I’s heir, Philip II of Spain, in 1544 married Maria Manuela, who was daughter of King John III of Portugal and his Spanish queen consort Catherine. Reciprocally again, John Manuel of Portugal, the heir assumptive of John III, married in 1552 the Spanish King Philip II’s sister, Juana, his first cousin. John Manuel was Maria Manuelas brother but, due to his premature death, he never ascended the throne. It was Philip II of Spain who finally ended the string of Spanish- Portuguese royal intermarriages, but only after his first marriage to the said Portuguese princess, Maria Manuela, who died prematurely. By the time of this marriage, Spanish-Portuguese intermarriages and inbreeding had continued for four generations, but still the Spanish royal family persisted with cousin marriages in its search for spouses from other royal dynasties. Philip II’s second wife was his first cousin once removed, Queen Mary of England. They married in 1554. Philip II’s fourth wife, Anne of Austria, was his first cousin once removed. This marriage was contracted in 1570.
Philip II’s marriage to Anne of Austria was not the first cousin marriage between the two Habsburg lineages. The first one was contracted in 1548, when Maximilian (II), the future Holy Roman Emperor and Archduke of Austria, wedded King Charles I’s eldest daughter Maria. During the time of the Habsburgs, marriages to cousins were unavoidable. Charles I of Spain (r. 1516-56) divided his realm into two sovereign parts: Austria was to be ruled by his brother Ferdinand I (r. 1526-64), while Charles himself continued to rule Spain (Ingrao 2003, 4; Sutter Fichtner 2014, 75-6). Ferdinand I and Charles I were the sons of the said Juana I and Philip I, whose daughters’ marriages to Portuguese kings we discussed earlier. There were numerous, almost constant cousin marriages between Spain and Austria from 1548 to 1666, when Leopold I of Austria married his niece and first cousin Margaret Theresa of Spain. Six generations of cousin marriages between Spain and Austria attest to multiple consanguinity.
In contrast to the numerous marriages into Portuguese and Austrian royal houses, there were only few cousin marriages between Spain and France. King Louis XIII of France married Anne, daughter of King Philip III of Spain, in 1615. Philip and Anne were not cousins, but Anne had a background of three generations of inbreeding: her father and mother were second cousins, her grandparents were first cousins once removed and her great-grandparents were first cousins. This may have contributed to the fact that only two of Louis XIII and Anne’s six children survived. The elder of them was Louis XIV of France, who in 1660 married Maria Theresa, his first cousin, who was daughter of King Philip IV of Spain. Not only were Louis and Maria Theresa cousins, then, but their marriage was burdened with a long line of cousin marriages in Maria Theresa’s family. Only one of their six children survived into maturity.
In the Protestant camp, cousin marriages were most common in Prussia: the 47 per cent rate was close to the average for Catholic monarchies. The series of cousin marriages was started by Frederick I, the first king in Prussia, in 1679. His first wife was his cousin, Elisabeth Henrietta from the Hesse-Kassel Landgraviate. Their only child, Louise Dorothea, married his first cousin, Landgrave Frederick of Hesse-Kassel, in 1700. In this generation, too, Frederick’s successor, Frederick William I, born from Frederick I’s second marriage, married in 1706 his first cousin, Sophia Dorothea, who herself was the daughter of two first cousins, King George I of England and his wife, Sophia Dorothea. In the third generation their son, Frederick the Great, married in 1733 his first cousin, Elisabeth Christine, but they did not produce issue. Furthermore, Frederick the Great’s successor, his nephew, Frederick William II, married his first cousin in 1765.
There has been much discussion about the disadvantages of inbreeding in European royal houses, focusing above all on hereditary diseases such as feeble-mindedness and other mental disturbances, deafness, blindness, haemorrhage and infertility (Kuper 2009, 83). With the single exception of haemorrhage I have found no systematic data on the occurrence of hereditary diseases in European royalty, but in my data set cousin marriages, particularly if they continued over successive generations, led to high incidences of infant mortality and childlessness. In the Portuguese royal house, for example, the unbroken line of cousin marriages from King John II (r. 1481-95) to the childless Sebastian I (r. 1557-78) resulted in high infant mortality and ultimately in the extinction of the dynasty. No less than 60 per cent of royal offspring died before the age of 20, most of them in early infancy. King John II of Portugal and his Spanish consort Catherine suffered the most unfortunate fate of all: every one of their nine children died prematurely. This line included several marriages between double first cousins. In the Spanish royal line from Charles I (r. 1516-56) up to Charles II (r. 1665-1700), an unbroken line of cousin marriages, 55 per cent of the children died before age 20, most of them in early infancy. This line became extinct in 1700, when King Charles II died without issue from his two marriages. Charles had a long list of physical and mental ailments which made his reign practically impossible, a fate already suffered by Juana I at the beginning of the sixteenth century (Maltby 2009, 33, 140). These findings suggest a close connection between high infant mortality and frequent inbreeding, although it must be borne in mind that in those days infant mortality could be high for other reasons, too. In Russia, for instance, where cousin marriages by all accounts were infrequent, the infant mortality rate was 57 per cent. Despite all this misery, cousin marriages did not lose their appeal among royalty.
So none of the impediments and prohibitions prevented monarchs from marrying their cousins, in sharp contrast to the imperative of common faith that the Church had decreed and that the monarchs scrupulously obeyed. Obviously, this difference reflected the huge significance of cousin marriages for royalty. The reason why cousin marriages were so frequent becomes clear when they are thought of in terms of the intensification of status equivalence, the other imperative that the monarchs were ready to obey at the time. The wedded cousins were united not only by their identical status, signified by the royal blood, but even more tightly by their own royal blood. This strengthened the status of certain dynasties, at the head of them the Habsburgs, who ruled two monarchies, Spain and Austria, and who strongly preferred their own kindred when making decisions about marriages. Identical status afforded a sense of familiarity, but presumably this sense was further reinforced when cemented by kinship ties. Since close ties did not prevent monarchies from going to war with each other, I am inclined to think that no rational cause explains the high frequency of cousin marriages. Rather, these marriages are reflections of a mystical bond that kinship establishes everywhere. However, this bond works differently in different contexts. At the time when status became a family matter in the foremost echelons, the imperative of status equivalence amalgamated with the logic of kinship, reaching its climax in cousin marriages. This also intensified dynasticity into high dynasticity, ingrained in the high consciousness of one’s own dynasty’s extraordinary value. This consciousness was at its zenith in most royal houses in their heyday. Spain is a good example of this tendency, and Prussia as well, where cousin marriages in four generations clustered around the time when Prussia was proclaimed a kingdom and her political standing was on the rise. It can also be suggested that frequent cousin marriages materialized the merger of the two parallel developments, the growth of the modern centralized state in the form of monarchism and the strengthening of family and kinship ties, as discussed by Sabean and Teuscher (2007, 2-3).