The settlement hill of Umm Qays in an exposed location of NW-Jordan with a view of the Sea of Galilee was identified as the decapolis city of Gadara as early as 1806 and has been excavated since 1959. This 3rd volume after the Late Roman arch [OrA 21] and research 1987-2000 [OrA 28] features the architectural and archaeological evidence, the strategic and military significance and the constructive subtleties of the small Seleucid citadel. It is firmly dated [1st half 2nd century B.C.] and well preserved in the east and south, while important city quarters remained unfortified. Its BA and IA predecessor at Tall Ziraa is attested archaeologically, a Ptolemaic fortress only by written sources. In the early 1st century the fortress was taken twice by Hasmoneans, restored by Seleucids and Romans respectively, but eventually covered by up to 7 m of soil and debris. The high-quality ashlar masonry in opus isodomum and pseudoisodomum consisted of local limestone and was virtually jointlessly laid by means of anathyrosis and gypsum mortar. Towers and pedestral are solid, upright walls with a core of plain stonework. Gates and rectangular and pentagonal towers integrate both Seleucid and Ptolemaic characteristics.