Confirming what everyone else has already said, you can purchase up to 3.and what does the 3/3 mean by the tomes? @helya
@Ihrlaen,With the (very) likely introduction of the Tome of Forbidden Wisdom coming to Live in the next FA, this is going to come up again, only for the Forbidden Ruins set.
And if you do have 2 extra pieces from silver and FA?when I confirmed to my satisfaction that it would require at 2 least buildings plus the Forbidden Ruins itself in order to generate CCs.