In the Late Middle Ages, the marsh and peat districts of the present provinces of Groningen and Friesland were converted into monastic landscapes in short time. Numerous monastic orders settled in the wetlands, contributing considerably to the transformation of a semi-natural into a cultural landscape. In 1192, a Cistercian monastery was founded at Aduard in Eastern Lauwers Frisia, which quickly became the focus of development of the Groningen marsh region. The Aduard monastery possessed over 5,000 hectares of cultivated land and was very active in peat reclamation for economic purposes, which required a well-maintained network of waterways, waterworks like sluices and country-roads. Yet little is known about the manner how these roads crossed over waterways, and whether bridges were constructed for this purpose.
The restoration of the historic bridge located near Aduard, Groningen (a monument listed as Steentil, meaning ‘stone bridge’) in 2009 offered an opportunity to gain more insight in this medieval water-engineering. Indeed, it revealed an early predecessor dating to the end of the 13th century, which was an unexpected surprise.
Figure 1 a) Location of the Steentil bridge near Aduard, province of Groningen (topographical map 1:25.000).