Later excavations, conducted by Duyuran between 1951 and 1952, found a column base in the portico of the church with an inscription identifying the site as the Palace of Antiochus.³ The stamped bricks excavated at the site combined with literary evidence date the structure to some time after AD 429.⁴ The church shows 6^th-c. stylistic features; however in literary sources this section of the palace is said to have been converted into a church so that the relics of saint Euphemia of Chalcedon would be transferred there from her church under pressure of the Persians, which points to an early 7^th-c. date (608/9 or 615 or 626, although in the Patria of Constantinople the church is wrongly attributed to Constantine I and the translation of the relics is set to the early 5^th c.).⁵

2. Remaining structure

The existing structure consists of a series of standing walls that vary between one and three metres tall arranged in a hexagonal plan, with a large absidal niche on each side. Between the niches there were small circular porches. The entrance of the secular building was to the south; to the right of this entrance, at the east niche and in front of it, the bema was inserted. Another entrance was opened to the niche across from the sanctuary, while the older one remained in use, though narrowed down at some later point. The date of the opening of a new entrance at the west niche is uncertain, but since, along with the bema, it creates a new east-west axis (instead of the north-south axis of the secular building), Mathews assumes that it should be dated to the period of the conversion of the structure into a church.⁶ In addition to these entrances, two more were opened in the circular porches flanking the apse of the sanctuary; they were eventually closed off with adjoining mausolea.⁷ The existence of such auxiliary entrances flanking the sanctuary is common feature of Constantinopolitan Early Byzantine churches, and it should be associated with the demands of the liturgy in the Early Byzantine capital.⁸

The excavations also brought to light remains of the synthronon, altar foundation, chancel barrier, and solea. It is possible that there had also been an ambo, although no evidence survives. These features conform to the arrangement of the sanctuary area as it is attested in other Early Byzantine churches in Constantinople.

The sculptural fragments from the chancel barrier, such as the octagonal column bases and the chancel-slab decorations point to a 6^th-c. date, as does the decorative technique of inlaying glass paste in marble on columns and slabs.⁹ On the other hand, the epistyle seems to have been Middle Byzantine and it is associated with a reworking of 797. During the Iconoclastic period the church was supposedly secularised and, according to the legend, Constantine V ( 741-775) (or, according to another variation, his father, Leo III (717-741)¹⁰ had the relics thrown into the sea and the church converted into a store for arms and manure. The relics were miraculously saved and washed up, or brought to Lemnos, from where Eirene Athenaia brought them back to Constantinople.¹¹ This return of the relics probably evokes actual restoration of the church after Iconoclasm.¹²

3. The frescoes

A cycle of fourteen frescoes still survives in the south west part of the church, and can be viewed behind a protective shield. The frescoes depict episodes of the life and martyrdom of Euphemia of Chalcedon, in rectangular panels outlined by red lines. The frescoes date to the last decades of the 13^th c. and parallel, in terms of colors and style, the frescoes of the original program of St. Demetrios (the metropolitan church) of Mistra (1275-80) and those of the chapel of the Virgin Pammakaristos (c. 1310), which, though of a sligtly later date, follow an earlier style.¹³ Some details, such as the use of different colours for rendering the contrast of light and shadow areas on the garments of the figures, remind even later developments of Palaiologan monumental painting in Mistra (such as the frescoes of Peribleptos, 1360-70). According to the stylistic trends of early Palaiologan painting, the figures in the frescoes of the Euphemia cycle are gaining in volume. In addition to this fresco cycle, there is also an unparalleled in Constantinople depiction of the martydom of forty Christian soldiers frozen to death in the Lake of Sevasteia (the Forty Martyrs of Sebasteia).¹⁴

4. Evaluation

The church of St. Euphemia is an important monument of Constantinopolitan religious architecture and art. Having been a secular palatial structure converted to a church, provides important evidence on the assimilation of the vocabulary of secular late antique architecture by the Early Byzantine religious architecture. Moreover, it has preserved traces of its internal arrangement as a church, thus offering a possible layout of the early constantnopolitan churches' liturgcal arrangement. Finaly, the 13^th-c. iconographc cycle of the martyrdom of Euphemia has no parallel in the art of the capital.¹⁵