Apamea is an ancient Roman site located near the modern city of Qalaat al-Madiq. It was founded in 300-299 BCE by Seleucus I Nicator (r. 301-281 BCE), one of the four great cities known as the Tetrapolis. It flourished through the 6th century CE, when excavators studying the city suggest that it was destroyed by earthquakes in 526 and 528, and despite systematic reconstruction, never recovered its splendor. The city was subsequently destroyed by a series of Muslim conquests in the 7th century.
The town covered an area of approximately 3 km². The town plan in its present state dates to the 2nd century CE. The main colonnaded avenue is oriented north-south and is crossed by two main east-west arteries, along with smaller side streets at regular intervals. The avenue has a paved street of 22.5 m wide and is nearly 40 m wide from the back of one covered portico to the other, and stretches nearly 2 km long, making it one of the longest in the Roman world. The colonnades were paved with mosaics in the 6th century. The avenue leads to many of the major public monuments in the city, including a Roman bath, a monumental nymphaeum, the agora, churches, and other structures whose function remains unknown. Apamea is the site of one of the largest theaters in the Roman world, with a diameter of 139 m.
Most of the excavated buildings in Apamea are in the southern part of the city, near the grand colonnade or the southern decumanus (east-west oriented road). These include three large churches - the Rotunda, the Atrium Church, and the Cathedral, and three mansions - the Triclinos House near the Cathedral, the Pilaster House on the decumaus, and the Console House adjoining it on the north. Several other large houses in the city have also been excavated.
Apamea has been heavily looted since the beginning of the Syrian civil war. Large holes that are visible in satellite photos were dug across the site between 2011 and 2012.