The Teutonic Knights constructed the fortress Tartlau in 1212-1213 as part of their colonization of the Burzenland region. The town of Prejmer near the castle had begun development by 1225, and was the eastern-most settlement of the Transylvanian Saxons. Prejmer was repeatedly invaded throughout the Middle Ages by various groups, including the Mongols, Tatars, Ottoman Turks, Cossacks, and Moldavians. However, the castle was only captured once, by Gabriel Báthori in 1611.The church is modeled after churches of Jerusalem, as well as built in the style of Late Gothic churches from the Rhineland. In the 15th century, it was surrounded by a wall 12m high, forming a quadrilateral with rounded corners. The wall was reinforced by four horseshoe-shaped towers, two of which have since disappeared. The entrance—a vaulted gallery—is protected by a barbican and flanked by a lateral wall. The defensive structure is strengthened by embrasures and bartizans, while the covered way is surrounded by a parapet. The granaries and rooms that accomodated the villagers are arranged on four levels above the cellars. The fortress is a UNESCO World Heritage Site.