The Church of Koimesis in Nicaea, originally the Monastery of Hyacinth, was destroyed in 1922. It was built by abbot Hyakinthos for his monastery, and several monograms of Hyakinthos decorated the church. The monastery played an important part throughout the Byzantine period, appears to have housed the patriarch during the thirteenth-century exile from Constantinople, and members of the imperial family were buried there. The church, which measured around 22x21, was centered on a dome supported by four piers and barrel vaults, which appeared as short cross arms. It has a triple apse and its walls of the naos were covered with marble revetment. The mosaics of the sanctuary are reconstructed with four phases. The nearby Böcek Hagiasma, a round structure with a water spring at the center of a quadrangular fountain, was also part of the monastery.