The present Basilica of the Nativity was built by the Emperor Justinian (527-565) on the site of the earlier (4th century) Constantinian basilica, which had been badly damaged in the Samaritan revolt of 529. The Basilica is dedicated to the Holy Mother of God (Theotokos). The traditional site of the Nativity is enshrined in the grotto beneath the choir.
The layout of the building is that of a classic basilica, with narthex, nave, four aisles (two on each side), choir, transepts and apse. The orientation is east-west, with the apse and sanctuary toward the east. Monumental stairways on either side of the choir lead down to the Grotto of the Nativity.
Doorways on the south side of the Basilica lead into the adjoining Greek and Armenian monasteries; doorways on the north side of the building lead into the (Roman Catholic) Franciscan Church of St. Catherine of Alexandria.
The main entrance to the Basilica is from the west. Two of the original 7th-century doorways have been walled up. The north portal is masked by a buttress; the south portal by a wall of the adjoining Armenian monastery. The remaining central portal has been reduced in size several times and the present low doorway has only 1.2 meters of headway.
The rest of the Basilica is architecturally as it was at the time of construction, though little remains of either the original or medieval decorations. Fragments of 12th-century Byzantine mosaics can still be seen on the upper walls of the nave. Traces of Crusader decoration are also visible on the pillars separating the aisles in the main body of the church. The upper portions of these pillars are painted with images of various saints of the Western and Eastern churches (among those depicted are St. Sabas, St. Euthymius, St. Olav of Norway, St. Canute of Denmark and St. Cathal of Ireland).
The roof of the Basilica dates from the 14th century.
Since the Crusades, portions of the church have come into the possession of the Greek Orthodox, Armenian Orthodox and Roman Catholic communities. The rights, privileges and possessions of these communities are protected by the Status Quo of the Holy Places (1852), as guaranteed in Article LXII of the Treaty of Berlin (1878).
The main body of the Basilica, including the nave, aisles, katholicon (choir and sanctuary), south transept, and the Altar of the Nativity in the Grotto are in the possession of the Greek Orthodox.
The Armenian Orthodox have possession of the north transept and the altar there. They also have use, on occasion, of the Greek Orthodox altar in the Grotto.
The (Roman Catholic) Latins have exclusive possession of the Altar of the Adoration of the Magi in the area of the Grotto of the Nativity known as the "Grotto of the Manger". The Latins also possess the silver star beneath the adjacent Altar of the Nativity that is inscribed, "Hic de Virgine Maria Jesus Christus Natus Est."
Both the Armenians and the Latins have rights of passage and procession in the Nave.
Sources: Israeli Foreign Ministry