Fort Joseph

Fort Joseph stands in Mainz-Oberstadt on the Linsenberg height, overlooking the Zaybach Valley in Germany. Roman aqueduct remains lie within the surrounding view. Built between 1713 and 1730, the fort formed part of baroque Mainz’s second fortress ring. Johann Maximilian von Welsch designed the fort for Mainz’s defensive network.

Elector Lothar Franz von Schönborn commissioned the work to secure Mainz’s interests along the Rhine. Fort Karl and Fort Elisabeth joined this defensive network. Crenellated walls connected the forts and helped relieve older bastions weakened by advances in artillery technology. A blockhouse covered the fort’s retreat area, while its position supported the wider defence of the city.

At the tip, a large open space covered the so-called holy valley, used for burials since Roman times. By the late eighteenth century, costly maintenance had left the fortress system in disrepair. French revolutionary troops captured the fortress in 1792. Today, the remains form a cultural monument where military architecture, a valley, and Roman traces meet.