Why did literacy in Europe decrease during the Middle Ages?

In the middle ages, literacy was not massively lower than in antiquity, because both lacked mass education and printing. Before large scale education and printing became possible, the overwhelming majority of people were non-literate agricultural workers.

Explanation:

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.

the answer to your question is,

old stone age.

-mabel < 3