A day for cousins, a history of cousin marriages

This week, on July 24, many countries celebrate National Cousins Day, a relatively recent celebration with obscure origins. Unlike Mother's Day or Father's Day, no documented individual or government established it. Historians generally regard it as one of the many informal American “National Days” that emerged during the latter half of the twentieth century through civic groups, greeting card companies, newspapers, radio stations, popular culture, and later social media. And, unlike official public holidays, it was never created by legislation.

Although National Cousins Day also has no legal status in the Philippines, many Filipinos mark July 24 by sharing old photographs, recalling childhood memories, and celebrating the special bond they share with their cousins. The day is also celebrated to revisit another aspect of family history that continues to generate curiosity and debate: marriages between blood relatives. While many call it incest, the more precise and less loaded terms are consanguineous marriage or endogamy.

Marriage between relatives is far older and more widespread than many realize. Yet throughout history, nearly every society has drawn a line between acceptable marriages among relatives and sexual relationships considered too close to allow. Such prohibited relationships, like parent and child, siblings, uncle and niece, aunt and nephew, or grandparent and grandchild, are known as incest. The word comes from the Latin incestum, meaning “impurity” or “defilement”. In Chinese, luanlun refers to disorder within family relationships, while the Indonesian word sumbang describes something improper or morally offensive.

Not every civilization treated all consanguineous unions alike. The Judeo-Christian tradition presents an interesting dilemma: if humanity descended from Adam and Eve, the earliest generations necessarily married within the same family. Ancient texts such as the Book of Jubilees describe brothers marrying sisters before marriages gradually extended to cousins and more distant relatives. Whether interpreted literally or symbolically, these accounts portray endogamy as an unavoidable reality in humanity's earliest beginnings.

Endogamy also characterized many ancient societies. Small communities naturally had limited marriage choices, while religious and political considerations encouraged marriages within ruling families. Among ancient Egyptian royalty, sibling marriages helped preserve dynastic legitimacy. During the Ptolemaic Dynasty, descendants of Ptolemy, one of Alexander the Great's generals, frequently married their siblings. Cleopatra VII famously married her brothers Ptolemy XIII and Ptolemy XIV.

Philippine history likewise provides numerous examples, particularly among ruling families and political elites. Before the arrival of the Spaniards, the ruling families of Manila practiced endogamy. The families of Lakandula, Rajah Matanda, and Rajah Sulayman belonged to a small circle of principales whose political alliances were strengthened through marriage. Rajah Matanda himself married his first cousin, both being grandchildren of Sultan Bolkiah of Brunei.

Perhaps the best-known cousin relationship in Philippine history is the documented first-cousin marriage within the Rizal family when Emiliana Rizal, the natural daughter of Paciano Rizal and Severina Decena, married Antonio Rizal Lopez, the son of Narcisa Rizal and Antonino Lopez.

Other political families also illustrate this pattern. President Manuel L. Quezon married his first cousin, Aurora Antonia Aragon, whose mother was the sister of Quezon's mother. Senator Benigno "Ninoy" Aquino Jr.’s parents, Benigno Sr. and Aurora Aquino, were third cousins. Senator Mar Roxas' maternal grandparents were fourth cousins. In 2002, Juan Miguel Macapagal Arroyo, son of President Gloria M. Arroyo, married Angela Arroyo Montenegro, his second cousin, while in 2017, Michael Ferdinand Marcos Manotoc, grandson of President Ferdinand E. Marcos, married Carina Amelia Manglapus, his second cousin.

These examples show that consanguineous marriages formed part of Philippine history and were not confined to ancient civilizations or royalty. More importantly, they remind us that attitudes toward cousin marriages have changed considerably over time. Relationships once accepted to preserve property, political alliances, or family ties are now viewed through a very different legal, cultural, and scientific lens.

Perhaps that is the greatest lesson behind National Cousins Day. Beyond reunions and nostalgic memories, cousins are not only lifelong companions but also invaluable links in our family history. For genealogists especially, they often hold the key to mysteries that have remained hidden for generations.