Why Why Why did knights wear heavy armour?

Format- Paperback 

Publisher- Miles Kelly

Condition of the book-  Pre Loved*

Product Description-

 Why why why did Knights wear heavy armour?

*Pre-Loved- These are the Pre-owned, Used books which are in a good condition. Undamaged cover, no missing pages, all pages intact (Eg no crease and tears)no underlining, highlighting of text, no damage to margins