It could be "Frailes", as in friars or monks, perhaps referring to Catholic priests that accompanied the Spanish in their galleons, or maybe referring to Inca priests that hid El Dorado to prevent the infection from spreading—although that would be a strange use of the world "fraile", when referring to natives it'd be more natural to say something like "sacerdote".
"Los Frailes han llevado la estatua a la cámara acorazada."
"The priests have taken the statue to the vault."
But I can't say for sure, because:
- I don't see why they would use the capital F for that word. Then again I think there were other strange uses of capitalization in previous texts.
- Looking at the font sample you gave, the letter "i" seems rather tall and that would not match the blurred picture. Why is that so tall, though? It looks like a capital "i" while all the others are lowercase.
- I don't remember the story well enough. I know it wasn't Francis Drake or the English because those arrived later, but was there any confirmation about who exactly put the sarcophagus where it is? Also, wasn't the document part of a cargo list from a ship or something?