Martyrius’s largest and best-preserved mosaic covered the floor of the refectory, or dining hall, the most magnificent structure in the monastery. Two rows of seven columns divided the 86-foot-long, basilica-style room into a main hall with two aisles. In the center of the hall, a ribbon of tesserae creates a seemingly endless pattern of circles and four-petaled rosettes, framed by a guilloche pattern of paired ribbons in interlaced curves. Although the columns are gone, their bases still jut up from the floor and four of their capitals have been discovered—each with a different design, a common feature in the Byzantine period. Between the columns lay rectangular mosaic panels, with varying designs incorporating lozenges and circles. Benches lined the walls. Here monks ate, studied and conducted certain religious rites celebrated outside the church.

A serving window in the southern wall connected the dining room with the kitchen, where hundreds of storage jars, pitchers, bowls, plates and cups were discovered. (The curved marble tabletop on which they rest came from the refectory.) Several of the dishes fell from a second story, above the kitchen, which may have opened onto the dining hall, allowing monks upstairs to take part in events in the main dining hall. The kitchen floor was covered with a white mosaic highlighted by an elegant panel of a bird standing beneath a fruit-laden grapevine that grows out of a jeweled amphora.