Here’s a great post by Marie Brennan at Book View Cafe: New Worlds: Marriage
At its core, marriage is a form of alliance. These days it’s first and foremost an alliance between the spouses, and usually for reasons of personal happiness, but that’s a product of the general focus on individualism that dominates our society right now. It used to be an alliance between larger groups than that. Families, or lineages, or businesses, or estates, or even entire kingdoms: the people directly involved were representatives of those groups, rather than acting solely for themselves. … the counterpart to alliance is inheritance; you often need or at least want offspring who will inherit the business, the land, the connections to the parent families.
I’ve been very pleased overall with how readers have responded to the politically motivated marriage of Innisth and Kehera in WINTER OF ICE AND IRON. Of course this relationship doesn’t work for everyone. Still, it’s the most unromantic sort of situation, which was historically certainly not rare for important people. Though I hope most readers appreciate the perhaps somewhat subtle romance that appears and grows within the political arrangement.
Anyway, Brennan then goes on to briefly mention odd marriage customs one might use in writing SFF. This instantly made me think of my very favorite odd marriage custom, seen for example here:
I have tried reading the book, btw, and kind of lost interest part way through. Setting and description: wonderful. Ghost bride plot element: wonderful. Protagonist: kind of a twit. I would like to go back and finish this story, though.
I just love the idea of the ghost bride. You could do all kinds of twists on that if you were developing a secondary world fantasy.
Even more interesting is the custom of marrying a tree, seen sometimes in India because it puts the astrological bad luck carried by the bride on the tree instead of her actual husband. This idea could be spun off into all kinds of interesting customs in a secondary world culture, tied into all kinds of deeper traditions and beliefs.
One very practical custom in Japan was, and is, the idea of adopting an adult male as the heir of a family, marrying him to a daughter of the family, and thus continuing the family line or establishing a younger son as the “first-born” son of a different family. Wikipedia has this to say about the custom:
The centuries-old practice was developed as a mechanism for families to extend their family name, estate and ancestry without an unwieldy reliance on blood lines. … From the point of view of the adopted son, it was not so much an increase of class position, but rather a way to receive an independent life by becoming a first-born son. This does not mean that there were no vertical jumps in the social stratum by less wealthy individuals, but it was significantly less common. By being adopted, second-born sons were able to take over as the heads of households, and become the leader of the family business as well as a leader within the community itself.
This sure goes right back to Brennan’s point about marriage (and other family structures) being used as a way to arrange family or business matters. It’s hard to think of customs very different from the ones you grew up with, which is why people who write fiction ought to pay attention to nonfiction for background and ideas that depart from the familiar. Brennan’s is an interesting post that serves as a jumping-off point for countless worldbuilding possibilities!