The "Player's Handbook" brought about other changes in the game and its character classes. Fighters, clerics, and thieves have improved hit dice over the previous edition. The effects of a character's strength score on hit probability, damage, weight allowed, and open doors rolls were changed. High intelligence conferred an increased chance for both spell knowledge and ability to learn languages. A high wisdom score now gave clerics a spell bonus, while low wisdom gave a chance of spell failure. New charts delineated the effects of constitution, dexterity and charisma. Each of the five main character classes and five sub-classes had its own experience table; for most classes it was now harder to gain promotion above third or fourth levels. multiclassed characters were also introduced.