A "versus" question

Question

When to use por la mañana vs. en la mañana?

Answer 1

I have found an old thread with a great answer:

http://www.spanishdict.com/answers/159652/por-la-tarde-vs.-en-la-tarde

From a native speaker from Spain:

In Spain, "por la mañana" and "en la mañana" would serve different purposes. "Por la manaña" would be a generic way of referring to any morning ("ayer por la mañana") or none in particular ("estudio inglés por la mañana"), just like in your example. "En la mañana" would have to refer to a particular day, like in "en la mañana del jueves pasado me pasó algo muy curioso" or "en la mañana del 7 de diciembre de 1942 comenzó el ataque a Pearl Harbor".

The attack at Pearl Harbor was 1941 - 005faa61, Oct 20, 2014

Well, I quoted the answer from a different user, when I quote, I normally don't feel I am at liberty to alter what they said. ;) - bosquederoble, Oct 20, 2014