The project is the first attempt for a stratigraphic recording of the building, which, today, houses Zosimaia Public Central Historical Library of Ioannina, Greece. A stratigraphy of historical and not geological time. From the Ottoman conquest of Ioannina in 1430, their Liberation in 1913, the Treaty of Lausanne and the exchange of populations (1923), the Italian and German Occupation to the independent Greek State. From the first building, a mosque, founded in the first half of the 17th century, until today, approximately 4 centuries have passed, during which important events for European, Greek and local history took place. They affected the building sequence and proved to be decisive for the formations and the stages of this memorable place. The digital application, with 3D modeling and virtual tour, depicts the phases of the buildings. From the Ottoman mosque, with two building phases, with a madrasa and an imaret (1618/1635-1930), to the building of the Municipal Baths, until 1987 and finally to the current Library building. According to the changing and innovative roles of Libraries, they too are called upon to play an active role in the development of a new form of Diplomacy, that of "Library Diplomacy", within the framework of Cultural Diplomacy.