Sakralne su građevine bile sastavni dio tvrđava koje su se ponekad gradile na ruševinama starijih crkava i samostana ranonovovjekovnoga istočnog Jadrana, uz preuzimanje njihova titulara. S obzirom na to da postoji reprezentativan broj tvrđava visokearhitektonske vrijednosti, u središtu su interesa šibenske i splitske tvrđavne crkve i kapele koje se sagledavaju na temelju terenskih, arhivskih i arheoloških istraživanja. Sacral buildings were an integral part of the fortresses, sometimes built on the ruins of older churches and monasteries in the early modern Eastern Adriatic, retaining their titles. Considering that there is a representative number of fortresses of high architectural value, the main focus is on the fortress churches and chapels of Šibenik and Split, which are studied based on field, archival, and archaeological research.