The 11th-century Hagia Sophia is Kiev's famous Orthodox Cathedral, which is designed to rival the St. Sophia Church in Constantinople. The cathedral is built in Baroque style and includes a cathedral with a golden-green roof, a bell tower and a monastery. After the completion of the Church of St. Sophia, it soon became the religious, political and cultural center of Kievan Rus. During the Soviet era, the cathedral building was once a museum, mainly collecting portraits from the 13th to 17th centuries and paintings and statues from the 18th to the early 20th centuries. There are also many archaeological artifacts and architectural models.