The castle Echzell was a Roman fort in today's center of the municipality Echzell in Wetteraukreis in Hesse . It was built by 90. Chr. Built and served to 260 n. Chr. Roman auxiliary troops as a military base to protect the Upper Germanic Limes in the Wetterau . Only in the 3rd century is known as a unit the Ala I Indiana Gallorum . The size of the camp makes it probable, however, that here a cohort together with a 500-man horse unit ( Ala quingenaria)was stationed. The fort was thus next to the castle Friedberg and the temporally preceding camps of Nida-Heddernheim to the most important military sites on the Wetterau Limes .