Chivalry
Chivalry spells consume Tithing Points, which can only be restored by donating gold to ankhs. These must be functional ankhs at which a player can resurrect. One gold will provide one Tithing Point, and Chivalry spells generally consume 10~20 per cast. A character may hold up to 100,000 Tithing Points at one time -- any further donations will be refunded to the backpack. Tithing Point costs are affected by Lower Reagent Costs, but the Book of Chivalry's displayed costs will not update to reflect this.
Training:
0-30: - Buy from NPC Paladin
30-45: - Hold a weapon in hand and cast Consecrate Weapon
45-60: - Cast Divine Fury
60-70: - Cast Enemy of One
70-90: - Cast Holy Light
90-115: - Cast Noble Sacrifice
Every Chivalry spell has a 100% success chance at 115 skill and higher. So it cannot be raised further.