SOFIA, BULGARIA—Fourteen types of marble thought to have been used as decorations in a grand hall, or aula, have been unearthed in an area of public buildings at the site of Ulpia Oescus in northern Bulgaria, according to an Archaeology in Bulgaria report. The room is thought to have been built to welcome Emperor Constantine I to the Roman colony in A.D. 328 for the opening of a monumental bridge crossing the nearby Danube River. The pieces of marble suggest that the room was adorned with finely carved columns of striped calcite, and wall encasings made of red jasper—a decoration reserved for imperial residences, temples, and places where emperors were received. The excavation team also found traces of brick pillars and underfloor heating in the grand hall. For more on Roman archaeology in Bulgaria, go to "A Dutiful Roman Soldier."