Evocare: to rouse, to summon. Yes, all Julian's students had long ago had their fill of evocation. There was a specific ancient Roman meaning (http://www.sacred-texts.com/cla/gibbon/01/daf01007.htm#fr_118) to the term, of course, a more technical one; but Camilla supposed that was not what was meant here.

As always, Henry knew best.

"Ideally, transmutation that can't be undone," Camilla added. "We take transfiguration classes here, only the thing is, what's transfigured can be returned to its original form. Or maybe you've got something else entirely? Illusion won't do much good, I'm afraid. It's got to be something quite solid and binding."