Yelli Camii

Located within the ancient city of Beçin Antik Kenti, which has been on UNESCO’s World Heritage Tentative List since 2012, is a historical place of worship in the Milas district of Muğla province.

Geographical Location and Historical Context

The mosque is situated at the Kepez site to the east of the ancient city and forms part of the Yelli Külliyesi, one of two külliyes constructed outside the city walls. Located approximately two kilometers from the urban center, this complex consists of a mosque, a medrese, and a hamam. It is believed to have been built in the late 14th century to meet the needs of a growing population and to establish a new residential quarter.

Architectural Features and Plan Scheme

Yelli Camii comprises a square prayer hall with a single dome and a two-bay rear prayer area to the north. It is regarded as one of the small-scale yet structurally robust examples of 14th–15th century Anatolian Turkish architecture.

• Material Usage: Three distinct materials were used in the construction: rubble stone, cut stone, and brick. Rubble stone was predominantly used for the wall bodies, while regular cut stone was employed for arches, lintels, cornices, and corner junctions. Brick was used for the dome, dome transitions, and the cross vaults of the rear prayer area.
• Roofing System and Structural Supports: The main dome above the prayer hall transfers its load to the walls through prismatic triangular zones. The rear prayer area is covered by brick-built star vaults and cross vaults.

The main dome above the prayer hall (Anadolu Ajansı)

• Entrances and Facade Design: The building has two separate entrance doors, one on the northern facade and one on the eastern facade opening into the prayer hall. The combined use of cut stone and brick on the facades creates a dynamic architectural rhythm.

Technical Details and Acoustic Solutions

Caminin dome structure contains embedded fired clay pots (testiler), placed both to reduce structural load and to optimize interior acoustics. These elements were documented during restoration works while preserving their original forms and have been prepared for display.

Material Analyses and Scientific Data

According to academic studies, the mortars and plasters used in the structure contain high levels of calcium oxide (CaO) and silicon dioxide (SiO2). Mineralogically, the main components of the mortars are calcite and quartz, with minor amounts of mica, albite, and dolomite also detected. Analyses revealed that the plaster mortars exhibit hydraulic properties, whereas the wall masonry mortars do not. Furthermore, the compressive strength of the plaster mortars was found to be higher than that of the wall mortars.

Excavation and Restoration Process

Comprehensive excavation and restoration works initiated in 2012 gained momentum in 2017 with the approval of a detailed project.

• Cemetery and Archaeological Findings: Excavations conducted on the western facade of the mosque uncovered a cemetery (hazire). The graves and skeletal remains were documented using archaeological methods and subsequently restored.
• Restoration Methodology: The existing fabric of the structure was preserved throughout. Repointing work was carried out on walls and domes, and reinforcement was performed using materials consistent with the results of mortar and plaster analyses.
• Current Status: As of 2021, the restoration of Yelli Camii was completed. The mosque has been preserved as a historical monument and restored for active worship.

Due to its location at the outermost edge of Beçin Antik Kenti and its authentic transmission of the architectural characteristics of its era, this structure holds critical importance in the history of Turkish architecture.