At the site of Agios Stephanos in Kos, at the periphery of Kefalos Bay and a short distance from the sea, the ruins of two early Christian basilicas were discovered in 1932 and excavated by the Italian archaeologist Luciano Laurenzi. Among the large number of the early Christian churches on the island of Kos, the basilicas of St. Stephen are distinguished because of their size and the level of preservation. They were probably erected during 469 and 554 AD, in the years between the two devastating earthquakes that struck the island, of which the second destroyed the monument.

The south basilica is larger in size and exhibits all the features of the early Christian churches: it is a three nave basilica with two colonnades , raised nave, narthex , atrium and an arch in the sanctuary. The main materials used for the construction of the church were reddish limestone for the walls and granite and white marble for the columns. Parts of the marble pulpit, templon and altar and traces of the synthronon still survive. The sculpture decoration of the surviving panels and fragments of mosaics and inscriptions attest to the great care in decorating. The second basilica, smaller in size, is attached to the north wall of the first. It is also a three nave basilica with alternating pillars and columns between the aisles, a narthex and an arch to the sanctuary. It retains parts of the synthronon, the templon and mosaics with floral and geometric motifs. Individual outbuildings, a square baptistery (incorporated to the NE), a diaconicon and a sacristy , complete the complex.