Church architecture developed under the patronage of the medieval Serbian state. The most distinctive piece of medieval Serbian architecture was the Studenica monastery founded by Stefan Nemanja, the founder of medieval Serbia ca. 1190. This monastery also featured significant works of art including its Byzantine style fresco paintings. Its church also features extensive sculptures based on Psalms and the Dormition of the Theotokos. UNESCO added this monastery to its list of World Cultural Heritage sites in 1986. It was the model for other monasteries at Mileševa, Sopoćani and the Visoki Dečani. The influence of Byzantine art became more influential after the capture of Constantinople in 1204 in the Fourth Crusade when many Greek artists fled to Serbia. Their influence can be seen at the Church of the Ascension at Mileševa as well as in the wall paintings at the Church of the Holy Apostles at Peć and at the Sopoćani Monastery. Icons and frescoes also formed a significant part of church art. At that time in Raška, Stefan Vladislav who founded at Mileševa a monastery and a church where three of his court painters -- Demetrius, George and Theodore -- worked on wall painting free from the strict canon law tradition. The influence of Byzantine architecture reached its peak after 1300 including the rebuilding of the Our Lady of Ljeviš (ca. 1306–1307) and St. George at Staro Nagoričane as well as the Gračanica monastery. Church decorative paintings and religious arts and crafts also developed further in the period. The most noteworthy painters at the time were Michael Astrapas and Eutychios (fl. 1294-1317) and before them, Deacon Jovan and Rufin.