Spaniards have two surnames - the first surname comes from the father and the second surname is the first surname of the mother. So if Juan Martínez Escudero and Marta Villanueva Cortés have a child then she or he will be called Something Martínez Villanueva. On a day to day basis the first surname is the one used - the double barrelled version is used for Sunday best.
Now there are lots of variations on this basic theme. For instance it is possible to reverse the order of the surnames - in the above case to give Something Villanueva Martínez. Or it is possible to carry forward a compound surname - Something Martínez-Escudero Villanueva. There are many more possibilities.
At times this causes Maggie and me some difficulties. Lots of times telephone sales people want to talk to Señor John (from Christopher John Thompson) and it can be quite difficult using a Spanish Internet site as many of them ask for your first and second surname and absolutely refuse to let you leave the spaces blank or put in some non obtrusive character, such as a dash or underscore. I'm sure that plenty of organisations here must think I'm related to Malcolm X in some way - Christopher Thompson X
Someone had told me that there were restrctions on first names too - that they had to be "Biblical" but I was put right on this the other day. The law apparently says a child can only have one compound first name or two simple first names and that those names can't be diminuitives nor can they be family nicknames. They can't they be names that "aren't real" or make it difficult to identify a person or cause confusion in relation to the sex of the person.
So in Spain there are can't be anyone named after the whole of the 1976 cup winning Manchester City squad, it has to be William and Benjamin not Bill and Ben, no Lords, no Blankets nor Apples and no boys named Sue. Furthermore you can't decide to call all your sons George (unless all the earlier Georges have died) and it has to be a Spanish name not a translated variant - so Maria not Mary and José not Joseph.
I don't suppose this law avoids the Spanish equivalents of names like Nebuchednezzar and Ezekiel but at least it would stop children being saddled with those trendy names that become an embarassment to them as soon as they get to school. Then again all of those Beckies, Vickies, Toms and Bobs would be in trouble.