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, Hungarians, Ottoman Turks, Cossacks, and Moldavians. However, the castle was only captured once, by Gabriel Bathory in 1611.
Prejmer is noted for its fortified church, one of the best preserved of its kind in Eastern Europe. Between 1962-1970, the Romanian government carefully restored it to its present condition; the restoration work was done under the direction of architect Mariana Angelescu and engineer Alexandru Dobriceanu. 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.