Umm ar-Rasas (Kastron Mefa'a) is a UNESCO World Heritage Site, inscribed as such in 2004. Its rich occupational history and remains represent several important archaeological periods in central Jordan. Extensive excavations were carried out in the northern part of the site by Studium Biblicum Franciscanum of Jerusalem in the 1980s. Referred to as Mephaat in a number of ancient sources from the Old Testament book of Jeremiah to Eusebius in his Onamasticon and as Kastron Mefa'a in the mosaic floor of St. Stephen's Church onsite, its archaeological connections relate primarily to the Roman, Byzantine and Early Islamic periods.
• The Roman Period -- The site boasted Roman remains, including a fortified Roman military fort.
• The Byzantine Period -- The intense expansion of settled populations throughout Jordan and beyond during the Byzantine Period is well documented archaeologically. Excavations at Umm ar-Rasas revealed numerous domestic structures, but of major note, 16 churches. Of these, the Church of Saint Stephen, constructed in the late 8th century AD (more than one hundred years after the Islamic "conquest" of the seventh century), contains one of the most spectacular and complete and largest mosaic church floors in Jordan. Nearby are the still-standing remains of a 15-meter high Stylite tower, built for ascetic monks to isolate themselves for varying periods of time.
• The Early Islamic Period -- While the Early Islamic expansion was tolerant of Christian structures and practices, Muslim prohibitions against human and animal figures ultimately motivated the scrambling of most mosaic portraits in the church floor; a few were missed in these purges.