: Myra, which constitutes the Demre district center of Antalya province, is an ancient coastal city located in the middle of the Lycian region, starting from Phaselis in the east and extending to the Gulf of Fethiye in the west. Myra developed during the Byzantine period and became the religious and administrative center of the Lycian region in the 5th century. In terms of its location, the city was a stopover and supply point for sea transportation in the Mediterranean, as well as had an important religious place with its churches containing the relics of the holy saints. Lycia was one of the areas in the Eastern Mediterranean where a lot of invasion and piracy activities took place. The geographical location of the Lycian region has made the region an open target for pirates and foreign powers throughout history. Between the end of the 5 th century BC and the first half of the 4 th century BC was a particularly difficult period in which the Lycian city-states struggled both among themselves and with invading foreign powers. After the conversion of Lycia to the Roman province in 43 AD by Emperor Claudius, the invasion and piracy gradually decreased. The peaceful environment of the region was disturbed by the attacks of the Sassanids at the beginning of the 7th century followed by Arab attacks that lasted for nearly 300 years. It is seen that the coastal cities in particular were affected by these attacks. As a matter of fact, during periods of severe attacks, the retreat of people to safer rural areas of mountains were supported by architectural remnants. The people living in the countryside have built defensive structures on the slopes and important valleys along the coast against the dangers that could arise from the sea. In the Classical and Hellenistic periods, when the attacks were intense, sheltered multi-storey buildings with the appearance of towers became the living place of people engaged in agriculture. Tower farmhouses continued to be used for rural area security during the Roman and Byzantine periods. In addition, during the Sassanid and Arab invasions at the 7th -9 th centuries, many small castles were built for rural security. A series of small castles of Byzantine period were identified during the surveys in the rural area on north of the city of Myra. Byzantine castles are located in the upper part of the Myros valley, stretching from the city of Myra to the Kasaba Plain. The castles, which are connected with each other, overlook the Myra and Kasaba plains and the Myros valley. Certainly, these castles were built to protect both the people living in the mountainous area and the ancient Roman road in the valley. One of these castles is located in the Ayiveliler, which is the subject of this article. In the article, it is aimed to introduce the architectural features of the castle, to evaluate its place and importance in the security of the rural area together with other defensive structures.