En aquello entonces vs. en aquel entonces

En aquello entonces vs. en aquel entonces
 

Dear members of the forum!

I imagine that since "entonces" is not a noun, "en aquello entonces is correct.

Comments are welcome.

Silopanna/Dean

The proper phrase is 'en aquel entonces.'

Rusty,

Tanks again.

Silopanna/Dean

I agree with Rusty. The expressions "en/por aquel entonces" and "en/por ese entonces" (meaning "back in that time") are adverbial locutions. I would dare to say "entonces" does work as a noun there, but this function is strictly limited to the whole expression. :)