One of the most important monuments of the middle Byzantine art and architecture that survived to our day is Hosios Lukas Monastery. It has been listed on UNESCO’s World heritage sites. It is set on the slopes of mount Helicon in Greece. The monastery consists of two churches merged together. The first church was built in the late 10th century to house the relics of Hosios Loukas. It was named the ‘Theotokos Church’. This church has a quincunx design which is also known as the cross-in-square or crossed-dome design. A quincuncial plan consists of nine bays where the central bay and the four bays at the corners are covered with domes or groin vaults, while the other four are covered with barrel vaults. In the early 11th century, the second church
