How many surnames do you have? From 2 to 1,024, generation by generation
Spanish ID cards show two surnames, but each one stands for a whole line of ancestors. Here is the full count.
Every generation doubles your surnames
In Spain you carry the first surname of each parent. But each parent carried two, and each grandparent two more, so counting backwards your surnames double with every generation: 2 from your parents, 4 from your grandparents, 8 from your great-grandparents, then 16, 32, 64… Ten complete generations give 1,024, about a thousand: hence this app’s name.
The “eight surnames” of the Spanish hit comedy Ocho apellidos vascos (“Eight Basque Surnames”, 2014) are those of your eight great-grandparents: three generations back.
The order they go in
One simple rule gives the order: your list interleaves your father’s and your mother’s. First comes your father’s first surname, then your mother’s first, then your father’s second, then your mother’s second, and so on.
For example, if your father is García Pérez Aguirre Etxeberria and your mother is López Ruiz Sanz Gil, your eight surnames are García López Pérez Ruiz Aguirre Sanz Etxeberria Gil. Each parent brings their whole list, and each of those lists was built the same way from their own parents.
If in some branch the mother’s surname comes first (Spanish law has allowed it since 1999), or a family has two mothers or two fathers, you only swap the order on that person: the rest of the list falls into place.
The gaps: “_”
Almost every tree is missing someone. When a surname is unknown we put “_” in its place so the rest keep their positions: García López _ Ruiz still says your third surname is your father’s second, even though we don’t know it.
That’s why it’s worth counting how many surnames you have in a row with no gap, and who you would have to research to fill the first one.
When an ancestor shows up twice
Ten generations give 1,024 slots, but not always 1,024 different people. If two of your ancestors were cousins, their shared grandparents appear twice in your tree, and so do their surnames. Genealogists call it pedigree collapse, and it is far more common than you might think in small villages and past centuries.
A repeated surname doesn’t always mean that (García repeats out of sheer frequency), but if the same rare surname turns up in different branches, look for a shared ancestor.
Find them all
A Thousand Surnames does the count for you: import your tree as a GEDCOM file or build it by hand, and see your surnames in order, shaped as a cookie, with how common each one is in Spain (INE data) and where it is most common today. It’s free, and your tree never leaves your device.