In the vicinity of the Heiligenberg, the ruins of the 11th century monastery of St. Stephan are located on Heidelberg’s Michelsberg. The monastery was founded in 1090 by the Benedictine Arnold and comprised a hermitage and a chapel on the front peak of the Aberinsberg. This was later followed in the 12th century by a monastery church in the Gothic style commissioned by Zundebold, provost at St Michael’s Monastery. After the monastery was dissolved in the 16th century following the Reformation, the new owner, Heidelberg University, released the ruins as a quarry. Between 1885 and 1886, the remaining monastery stones were used to build the observation tower overlooking the castle and the Neckar valley.
