After leaving the village of Yavuzlu, 10 km along the main Gaziantep-Kilis road, you will see on your left a tumulus, Oylum Höyük. It is located south of the main road in the district of Oylum. The tumulus is 460 m long and 370 m wide, and consists of two raised domes, one 22 m and the other 37 m in height, connected by a single neck. These dimensions make it not only the largest tumulus in the Kilis Plain, but also one of the largest in the Southeast Anatolian region.
The tumulus sits on the fertile land between the high Anatolian plateau and the plains heading out to Syria, and has a commanding view over the Kilis Plain. This region lies at the northwest end of the Fertile Crescent which stretches from southern Mesopotamia to Palestine. The tomb found at the tumulus belongs to Yusuf İzzettin Hamra, who some say was a scholar and a religious man from the blood line of the holy Ahmed Rufai. During a visit to Kilis, he became ill and died at this site.
Approximately 600 m southwest of Oylum Höyük, in a field on the western side of the Akpınar River, stands a Byzantine basilica with mosaics, dating from the 6th century AD.
The floor of the basilica is covered with red, black, grey, white and yellow coloured mosaics, using botanical and geometric motifs such as intersecting circles, diamonds, squares, zigzags, leaves and Maltese cross. In the northeast section of the basilica, in the northern nave, there is a mosaic epitaph written in ancient Greek.
The Church with Mosaics has been temporarily covered and put under protection; it is planned to be converted into an open-air museum as a cultural asset for tourism in the region in the near future.
Due to Oylum Höyük being located at the interesection of routes stretching east-west and north-south, it has held a significant strategic importance over many different periods.
The Akpınar River, which rises in the Kilis Plain and flows all along the western foot slopes of the tumulus, provided life for the settlements. The 5,500-year-old dam, found on the western foot slopes of the tumulus, is an indication that in the past the Akpınar River flowed strongly here, even though the flow is much less today.
Since 1989, there have been continuous excavations at five different sites around the tumulus and at the “Mosaic Basilica” site to the west of the tumulus. Data from these excavations reveal that there have been continuous settlements at the Oylum Höyük site from the Late Chalcolithic period (3500-3000 BC) until today.
Findings dating from the Middle Bronze Age include charred olives, grape seeds, wheat and barley grains which shed light on the deep-rooted history of these fruits and crops still being grown widely on the Kilis Plain. The excavations revealed a workshop with two chambers attached to one of the houses and here various findings relating to glass production were uncovered. Numerous hearths, slag, cinder, and grinding stones show that the place was probably one of the oldest glass-making workshops in the world. Roman coins dating from the 4th century BC were found within the monument building located on top of the northwestern dome.