The 12th-century church of the Virgin Mary Gorgoepikoos, also known to Athenians as Agios Eleftherios, or the small cathedral, is located in Mitropoleos Square. Its cruciform configuration and extremely well-preserved dome make it the best-preserved example of the Athenian-style dome structure.

While the church is based upon a simple, brick-enclosed design, the upper part of its masonry features dozens of beautiful reliefs from all of the city’s historic eras. Most of the church’s interior frescoes were painted later, during the 20th century.