Though situated outside of the gate of the northeastern citadel, outside of the Aslan Pasha religious-educational complex, the Citadel Library is considered to be a part of that complex. The building was constructed after the mosque and madrasa, sometime in the 18th century, on a site with evidence of earlier Byzantine buildings.
The masonry of the building consists of medium-sized limestone blocks with sporadic use of brick, and the upper level is plastered. The library is built on two levels, with an open colonnaded porch covered by a wooden roof on the upper level, reached by a stone staircase. Two unequal arches support the staircase; the larger arch directly underneath the landing serves as the entrance to the ground floor utility rooms. Along the porch are three small domed rooms, with the middle one open to the porch and providing access to the other two. This middle room also leads to the main room of the building, the reading room. The reading room is a square space with many windows, covered by a hemispherical dome.
The building was completely restored in 1980, including rebuilding the ruined central dome and stabilizing the masonry. It has been systematically maintained since, and today the building is used as the offices of the workers union of the Ministry of Culture.
Brouskarē, Ersē, and Elizabeth Key Fowden. Ottoman architecture in Greece, 167. Athens: Hellenic Ministry of Culture, Directorate of Byzantine and Post-Byzantine Antiquities, 2009.
Mikropoulos, Tassos A., ed. Elevating and Safeguarding Culture Using Tools of the Information Society: Dusty traces of the Muslim culture, 374-375. Ioannina: The Educational Approaches to Virtual Reality Laboratory, University of Ioannina, 2008.