Hypnotize
From Populous Wiki
Hypnotize is a Spell that temporarily converts enemy followers to your own. Hypnotized followers can be recognized if they have a curling round on top of their heads. After a while, hypnotized followers are changed back to their original tribe and the rounds on top of their heads disappear.
Trick: To preserve a hypnotized follower, send him to one of your training huts.
Ex. You hypnotized an enemy brave. Then you send him to your Warrior Training Hut. When he goes out, he's now a Warrior and is permanently converted to your side!:-)