Altars also create the domain of the gods. You know when you're in such a domain when you get the message "You feel the presence of <god>".
Domains can overlap, but only the strongest domain can effect affect you. When you are in the domain of your [[Gods|God]] and have at least 10 faith, you'll get certain bonuses, including a [[fighting]] bonus. The amount of the bonus is effected by a great number of things, such as faith, [[alignment]], the type of the altar (see below), the distance to the altar, the [[quality]] of the altar, and if you're a [[Champion]].
Priests also get a bonus of up to 20% to successfully cast a spell, and it increases the chance of casting a higher strength enchant spell.