Guild bonuses
With each level, the guild bonuses will increase.
Prestige bonus
o Adds prestige to the guild’s daily prestige ranking
Support pool bonus
o Adds to the guild’s support pool (attack/defense bonus in GvG)
Player bonuses
Some levels will also provide a player bonus:
Recruitment boost
o Reduces the time needed to recruit units (new times are shown in the recruitment screen)
Research boost
o Gives additional forge points each day in your town hall
Construction rebate
o Reduces coin and supply cost of all buildings by a percentage (the original cost is shown in the research tree, and the reduced cost is displayed in the building menu).
(if you want a link (with the GvG user guide above):
http://forum.beta.forgeofempires.co...attles-are-here!&p=11724&viewfull=1#post11724)