I'm not sure how many volumes there are to the We Were There Series. They are historical fiction...easy to read and to understand. Great series to collect. Pick and choose the ones you want. Many of these authors went on to have even greater careers as authors.
When the peaceful life of ancient Redwall Abbey is shattered by the arrival of the evil rat Cluny and his villainous hordes, Matthias, a young mouse, determines to find the legendary sword of Martin the Warrior which, he is convinced, will help Redwall's inhabitants destroy the enemy.