This article provides a general overview of the history and geography of ancient Juliopolis, which was on the main route from Constantinople to the eastern parts of the empire, for military campaigns and pilgrimage. Even though Juliopolis drew the attention of early scholars such as: Anderson, Ramsay and French, who worked on the Pilgrim's Road, no systematic research had been conducted at this site until a team from the Museum of Anatolian Civilizations at Ankara began conducting regular excavations from 2009 onwards. The preservation works carried out around Nallıhan, together with these excavations, both by the museum, brought much new material into view, providing more information concerning this region in antiquity.