The ancient quarter where the St. George Rotunda is situated has 61 m length and average width 36 m. The position of the building allows the place in front of its entrance to be the most spacious. The four streets around the church pass it by on a lower level. This shows they were built in the beginning of the 2nd century and had existed before the built of the Rotunda. The remains can be dated as early as the first quarter of the 4th century. It is raised in the Old Christian age and therefor, if it has served for any cult purposes, it was for the needs of the Christian cult. Because of its form it can be assumed that probably it was a martyrion.
Later on, probably in the last quarter of the 4th century, the building is turned into baptistery (baptisterium) to satisfy the growing needs of Christianity of that kind of buildings. Since then had begun its bloom until the year if 447 A.D. when it was destroyed by the Huns. In the end of the 5th century it was just an insignificant, half demolished church. It existed like this till the 11th century when the rotunda and the narthex were reconstructed, the windows - resized and the building was painted in the way it can be seen today.
It is assumed that like inside outside it was plastered up. The preserved several layered frescos inside looking like a colourfull spots at first diverge from the commonly used principles in the Byzantine art. The flooring was probably made of marble or bricks. The building was tiled. The hypothesis that the existing hypocaust is a heating installation is rejected.
Many graves are found here, most of them grouped outside the building's outline, northeast of the apse.