In 1919 a cousin in New York wrote my great-grandmother a long letter about her Spanish ancestors. Her great-grandfather, Don Juan López Calleja Menéndez San Pedro, was born "in the Asturias" around 1800 and became a planter at Puerto Príncipe (today Camagüey), Cuba — a fortune the same letter says rested on "a great number of slaves." His two extra names, the letter said, were "a mark of honor granted to families which had distinguished themselves in the wars with the Moors," and the proof was kept "in an iron box at their City home," then "sent to Spain for confirmation of some legal matters," and lost. A generation later it had become a family story about descent from Ferdinand and Isabella.
Finding it. A two-word search of PARES, the Spanish state archives' online catalogue, for López Calleja turned up a nobility suit (pleito de hidalguía) at the Real Chancillería de Valladolid, the court that ruled on nobility for northern Spain: three brothers, Juan Antonio, Manuel and Isidoro López Calleja, of Laredo on the Cantabrian coast, 1776. The catalogue called it one folio, not digitised. I wrote to the archive's reference desk in September, accepted their quote (€24.60 for colour scans, paid by bank transfer to the Spanish Treasury), and today a download link arrived. It wasn't one folio. It was 164 pages.
What the file says
The surname starts here. The brothers' father was Luis López Pérez, born 14 January 1685. Their mother was María Antonia Calleja, a girl from the mountain town of La Vega de Pas who grew up in Laredo. The sons joined the two names. "López Calleja" isn't an honour from the Reconquista; it's a López who married a Calleja.
They were poor. The parents had never proved their nobility in Laredo "por la falta de medios" — for want of means. A town official said in 1777 that Luis had lived "muy corto de medios, y en suma estrechez y pobreza."
They were sailors. Five old men of Laredo, aged 74 to 82, swore in January 1777 that the father and sons had served the King "en calidad de marineros, en sus reales bajeles" — as sailors on his ships. One had sailed on campaigns with two of the brothers himself.
The eldest couldn't write his name, and went anyway. In May 1776 Juan Antonio, 47, travelled "more than eighty leagues" over mountain roads still under snow to his grandfather's village. The judge opened the village chest and the clerk copied the 1731 tax roll: "Juan López, hijodalgo notorio de sangre; Domingo, Juan, Luis, Josef y Pedro, sus hijos, de la misma calidad" — his grandfather, with his father still a boy at home among five brothers.
It reaches back to 1660. The parish books gave the grandfather's baptism (10 May 1660), his marriage to Leonor Pérez (28 January 1684), and Luis's own: "a boy named Luis, born on the fourteenth" of January 1685.
They won. Laredo's council recognised them in July 1776. A royal prosecutor objected, their old neighbours testified, and on 12 March 1777 the court in Valladolid ordered the final royal provision issued.
A tip for anyone whose records say "Asturias"
Every page calls the family's home "La Puebla, in the bishopric of Oviedo, in the Principality of Asturias." When the judge there signed his name, it turned out to be La Puebla de Navia de Suarna — today in the province of Lugo, in Galicia, but then inside the diocese of Oviedo. In old Spanish records "Asturias" can mean the diocese, not the modern region, so look across the border too.
What it doesn't prove
The file never mentions Menéndez, San Pedro, the Moors, or the man a cousin's family tree names as Don Juan's father. The surname, the first names (Juan, Manuel and Isidoro — names Don Juan later gave his own sons), the "Asturias" and the generation all fit, but no document yet connects these brothers to him. So it's a strong lead, not a proven line, and the legend stays a legend. The house behind it, so far, is a López who went to sea.
Next: I've asked the Archivo Histórico Diocesano de Oviedo for Don Juan's own baptism (Pravia, about 1801). A baptism of that period usually names both sets of grandparents and where they came from, which should settle it either way. The Laredo parish books after 1739 are the other half; the Santander diocesan archive takes requests through its form when it reopens on 9 November. If you've worked with either archive, I'd love to hear how long they took.
The documents (members only)
Five pages to start with:

The marriage of Luis López and María Antonia Calleja, Santa María de Laredo, August 1723, copied from the parish book in 1776. (p. 59)The village tax rolls of Navia de Suarna, read out on 19 May 1776: the 1731 roll lists Juan López and his sons Domingo, Juan, Luis, Josef and Pedro. (p. 109)The parish book of Villarpandín: Juan López's baptism, 10 May 1660, and his marriage to Leonor Pérez, 28 January 1684. (p. 110)Luis López's baptism, 15 January 1685: "a boy named Luis, born on the fourteenth." (p. 111)
Oviedo answered the same day. The Archivo Histórico Diocesano de Oviedo says Pravia has many parishes, and they need documentary proof of which one before they'll search. That's the problem: the only source for "Pravia" is a cousin's family tree, not a document. So I wrote back honestly, saying there's no proof, and asked whether they could check just one parish, Santa María la Mayor in the town of Pravia itself, for 1799–1802. If they can't, I asked whether the books can be seen in person, through a researcher, or in a digitised copy.
Why the baptism matters. An entry from around 1801 usually names both sets of grandparents and where they came from. If Don Juan's grandfather turns out to be one of the three Laredo brothers in this file, the line is proven. If the names don't match, the lead is dead. Either answer is worth having.
Why Lugo is next. This file puts the family's origin at La Puebla de Navia de Suarna, not Pravia. Today that's in Galicia, and its old parish books are with the diocese of Lugo. A family that always said "La Puebla, in Asturias" could easily have become "Pravia" a few generations later in Cuba. Lugo doesn't take requests by email: it wants a signed request form, an ID, and proof of kinship sent through its certificate form. That one goes out next.
And Santander. The Laredo parish books after 1739 are the other half. That archive takes requests through its form when it reopens on 9 November.
If you know Pravia's parishes, or you've had a record out of Lugo, tell me how it went.
A correction to my last update: Santander comes before Lugo.
I said Lugo was next. On a second look, it isn't. The family had left Navia de Suarna by 1723: Luis López was in Laredo by then, and his three sons were born, married and living there by 1776. If Don Juan descends from them, he was born about three generations after the move. He'd have been baptised in Laredo, or wherever that branch went next, not back in the Galician village. The Navia de Suarna books from 1660 to 1685 are already copied into this file, so Lugo would mostly hand back what's here.
So the order is:
Santander, for the Laredo parish books after 1739. This is the one that can decide the question. Look for the brothers' children and grandchildren, a Juan López Calleja who married a Fernández, or a son Juan born around 1801. It goes in when the archive reopens on 9 November.
Oviedo, for Pravia around 1801. This is already asked. If the family tree is right about Pravia, his baptism names his grandparents and settles it.
Lugo stays on the shelf unless one of those points back to Galicia.