Boyana Church was built in three stages, namely; in the late 10th to early 11th, the mid-13th, and the mid-19th centuries.
The oldest section (the Eastern Church) is a small one-apse cross-vaulted church with inbuilt cruciform supports. This building belongs to the two-floor tomb-church type.
It consists of a ground-floor family sepulchre with a semi-cylindrical vault and two arcosolia on the north and south walls, and an upper-floor family chapel identical in design to the Eastern Church. The church owes its world fame mainly to its frescoes from 1259.
They form a second layer over the paintings from earlier centuries and represent one of the most complete and well-preserved monuments of mediaeval art in the Balkans.
The Boyana Church owes its world fame above all to the frescoes from 1259, which demonstrate the exceptional achievements of mediaeval Bulgarian culture. The majority of the more than 240 figures depicted here display individuality, remarkable psychological insight and vitality.
The frescoes follow the canon of icon-painting established by the Seventh Ecumenical Council held in Nicaea in 787.
The lunette above the entrance of the narthex displays the Virgin and Child, St. Anna and St. Joachim, and Christ Blessing. St. Catherine, St. Marina, St. Theodore the Studite and St. Pachomius are portrayed in the lower tiers on the walls.
The south arcosolium features the scene of Christ Disputing with the Doctors, and the north one, the Presentation of the Virgin.
Two highly revered Bulgarian saints are also represented in the narthex – St. John of Rila (the oldest surviving representation of the saint) and St. Paraskeva (Petka). The hermit St. Ephraim Syrus appears among the monks portrayed here.
The oldest Boyana Church, the so-called East or First Church, was designed and used as a chapel. It had a typical Greek cross plan with a dome, and a concealed internal cross without free-standing support and without a narthex. It is built entirely of brick.
The north and south facades are articulated on the outside with three blind arches, each with the central arch higher than the side ones; the arches are not related to the structure of the building.
The brickwork decorations are figural: archivolts with ‘wolf’s tooth’ and concentric rows of bricks above the arches. In the 13th century the feudal ruler of the western region of the Second Bulgarian State, Sebastocrator Kaloyan and his wife Desislava, who were closely related to the royal family, commissioned the extension of the church.
The builders added a new two-storey building to the western wall of the First Church. The ground floor has direct access from the First Church and was intended as a narthex.
It is rectangular, covered with a cylindrical vault. On the inside, the walls are decorated only with two niches on the southern and northern sides respectively, probably for a family tomb.
The upstairs floor of Kaloyan’s Church has an almost identical architectural composition to the older building, in the shape of a Greek cross, and it was used as a family chapel. It was dedicated to the martyr healer St Panteleimon.
Access to the chapel is by an outside staircase along the southern wall. It is possible that the stairs connected the chapel with the house of the nobleman.