Part of the Chrestomanci series
Casa Montana and Casa Petrocchi control all the magical business in Caprona, watched over by its magnificent guardian statue, the Angel. But the families have been feuding for years, so when all the spells start going wrong, they naturally blame each other.
Set in a parallel world, in Italy.
LR 7/10 An enchanting book, one of the lighter reads of the Chrestomanci series but all the better for it.
The similarity to Romeo and Juliet is a hint offputting, but still an excellent read.