Borgia's Towers | Rome Restoration AC: B Guide

Sometime you won't be able to restore the building because it will be in the Borgia's area. To change this - destroy his tower [1]. At the beginning, find the commander and kill him [2]. If you will be too slow, he will run away - wait few minutes and try again.

After the execution, climb on the top [1] and press B to set the fire [2]. As a matter of fact, you will unblock nearby buildings.