The church is inside the actual cemetery, southwards to the Kos city. The ground
plan shows a circle with four semicircular corner conchs and one in the middle
of the eastern side, inscribed in a quadrangle. Two more conchs in the middle
of southern and northern side, along with the five mentioned above, gave the
church this name. One concentric colonnade in the interior, formed of eight unfluted
columns, has been replaced by walls. The entrance is in the middle of the western
side of the church.
The church was originally an early christian baptistery of the 5th
- 6th century, which belonged to a basilica, partly excavated and complemented
during the Italian occupation. No trace of it is seen today. It is perhaps the
only early christian baptistery, that has remained almost intact up to this day
and remains still in use as a cemetery church.
Frescoes of 12th - 13th century, with scenes of the life of St. John
the Precursor have been recently discovered, as well as others of the 16th century.
The church' s masonry presents some interesting elements, such as the use of hellenistic
frieze with garlands on the lower part of the sanctuary apse, architraves, bases,
early christian mullions, pilaster- capitals etc. in various parts of the walls.