Four Forts of the Deccan which presents four significant fortifications of South India, namely Daulatabad, Mudugal, Gandikota and Gutti, each of which furnishes evidence of the excellence of the military architecture developed in the Kingdoms of the Deccan between the 13th and the 18th centuries. The main purpose of this study is to analyse the building techniques in order to establish the typology of the works and to bring into focus a reliable method to identify and date them, an investigation which permits to show the evolution of the defence systems in this part of the Indian peninsula, considering their adaptation to the progress of artillery.