Kloster Stuben, Augustinian monastery ruins in Moselle Valley, Germany

Kloster Stuben is the ruin of an Augustinian convent on a peninsula by Bremm on the Moselle. Only the outer walls of the church remain, 45 metres long and 10 metres wide, with the west wall gone and the interior open to the sky. The former monastery grounds are now vineyards of the Abtei Kloster Stuben single-site wine brand.

Egelolf, a nobleman, gave Abbot Richard I of Springiersbach his castle house, a chapel and land on the tongue near Bremm at the wish of his daughter Gisela, who became the first abbess. Archbishop Albero of Trier confirmed the foundation in 1137 and limited the convent to 100 women. In 1208 the knight Heinrich von Ulmen gave the staurothek he had brought from Constantinople; the church and cross chapel were rebuilt in 1685–1687, and the abbey was dissolved in 1802.

The name Stuben comes from 'stuba', a heated room or small dwelling where the nuns lived; the Latin name was 'sorores de insula beati Nicolai in Stuppa', meaning sisters on St Nicholas's island. The monastery's seal showed the Stuben cross, St Nicholas and the Byzantine double cross also seen on the staurothek. Since 1959 the relic has been central to the Cross Festival established by Bishop Wilhelm Kempf.

The church ruin stands on a peninsula by Bremm on the Moselle, and the former monastery grounds are now vineyards of the Abtei Kloster Stuben single-site wine brand. Only the outer walls of the church remain, measuring 45 metres long and 10 metres wide, with the western wall gone, so the interior lies open to the sky. The site is a stop on walking routes along the Moselle near Bremm.

The monastery's seal showed the Stuben cross, Saint Nicholas and the Byzantine double cross also found on the staurothek. That reliquary, holding a 7 mm fragment of the True Cross brought from Constantinople after the Fourth Crusade, is now in the Limburg Diocesan Museum and since 1959 has been the focus of the Kreuzfest instituted by Bishop Wilhelm Kempf.