St Achillius Church, Arilje, 13th century

The church of Arilje is dedicated to Saint Achillius, bishop of Larissa, Greece, a staunch opponent of the Arian heresy and a participant of the First Council of Nicaea in 325 AD. The church in Arilje had close connections to the Nemanjić Dynasty, the first Serbian Archbishop Saint Sava, and King Dragutin.

Architecturally, the church belongs to the Raška stylistic group, characteristic of the 13th century and distinguished by its coherent blend of Romanesque exterior elements and Byzantine spatial concepts. The facade is decorated in the Byzantine style of cell patterning, combining layers of stone and brick, while the walls are Romanesque in style, which makes the church of Saint Achillius in Arilje unique in the 13th-century architecture of the entire Byzantine world.

The church in Arilje contains the tomb of Urošic, the younger son of King Dragutin, which is suggestive of the importance of this church to the king and may indicate that one of the royal courts might have been located near Arilje.

During the reign of Emperor Dušan, the Eparchy of Moravica was raised to the rank of a Metropolitanate, following the proclamation of the Serbian Patriarchate in 1346.

In addition to its architectural value and historical importance, the church is also noted as a gallery of valuable frescoes. The portraits of the rulers from the Nemanjić Dynasty, their relatives, and all archbishops from the time when the Serbian church gained its independence represent the most exciting part of the fresco group. A new iconographic solution was used here for the first time in the history of Serbian fresco painting. In earlier frescoes, it was typical to present founder compositions with the Mother of God or a patron saint leading the founder towards Christ on his throne, while the founder was shown with his head bowed and holding a model of the church in his hands. Here, the Son of God was painted on a small scale, on a medallion between the heads of front-facing portraits of the kings.

The Blue Angel fresco is among the greatest masterpieces of old Serbian art. The fresco of the Holy Archangel Gabriel, the Blue Angel, with a fair and dignified face, clad in a simple, luminous tunic, embodies the idea of the Lord's messenger and represents him in ethereal beauty with remarkable artistic skill. Of particular historical significance are portraits of Dragutin's sons Vladislav and Urošic as well as the portraits of Serbian archbishops, members of the Nemanjić Dynasty, and bishops and metropolitan bishops of Moravica. Names of the artists responsible for the Arilje frescoes are unknown, but it was recorded that they had come from Thessaloniki. In terms of style and iconography, these images announce a point of change in the development of Serbian fresco painting. They show the earliest beginnings of a new technique, which would become typical of the painters at the court of King Milutin and the visual arts in Serbia in the early 14th century.

The Church of Saint Achillius, as a cultural monument of exceptional importance, is under protection based on the Decision rendered in 1947 by the Institute for Protection and Scientific Research of Cultural Monuments of the Republic of Serbia.