Lamentation (The Psalms of Isaak)

The setting is a fantasy world with a little bit of magic in form of artifacts. The wisdom is stored in a big library. The book starts with the annihilation of the city where this library and most academics reside. This changes the society completely. Consequently 5 parties making war, forging alliances, and try to rule the new world. It is unclear who is responsible for the destruction of the city, but after some time the truth is revealed. This changes the constellation of power.