Summoning in Heroes 4

Basic Summoning gives the hero the ability to summon leprechauns, sprites, or wolves into the hero's army every day at a rate of 10 experience points of creatures per day.

Advanced Summoning gives the hero the ability to summon leprechauns, sprites, or wolves into the hero's army every day at a rate of 20 experience points of creatures per day.

Expert Summoning gives the hero the ability to summon elves, satyrs, or tigers into the hero's army every day at a rate of 30 experience points of creatures per day.

Master Summoning gives the hero the ability to summon elves, satyrs, or tigers into the hero's army every day at a rate of 40 experience points of creatures per day.

Grandmaster Summoning gives the hero the ability to summon earth, air, fire and water elementals into the hero's army every day at a rate of 50 experience points of creatures per day.