Mensaje en clave que Daniel Defoe habría mandado a alguno de sus amigos desde la prisión.

I inferred you want a representation of the text in English.

Explanation:

It reads;

"Code message that Daniel Defoe would have sent one of his friends from prison".

I highly feel the text is referring to the English man Daniel Defoe who was a very familiar author back in the 1600s. His interest in politics were noteworthy as this landed him prison. So it is more likely that his letters to friends from prison be political in nature

always in school geography and mathematics.

( i don't know what exactly this means but i translated it : d )