In landscape archaeology, geophysical methods are increasingly being applied to conduct large area surveys1. Although these techniques allow obtaining high-resolution archaeological information at a landscape-scale2,3,4, they often neglect natural landscape variations. To fully understand the driving mechanisms behind human land-use, the integration of pedological and geomorphological information in these prospection stages is crucial.

In Europe, one of the most characteristic examples of past human-landscape interaction, is the reclamation of wetlands and forest that followed the urbanisation of the historical County of Flanders (Fig. 1b). During Medieval periods, these lowlands experienced a considerable population growth, making the County one of the most densely populated areas in Europe between the 11th and the 15th centuries5. To meet the demands of emerging cities, such as Ghent, Bruges and Ypres6, entire natural landscapes were reclaimed, transforming these into a landscape of dynamic exploitation7. The ruling Counts of Flanders spearheaded this evolution by endowing feudal lords with lands, while abbeys were deliberately installed on marginal land all over Flanders.

Figure 1 Location and historical context of the site. (a), The location and elevation32 of the study area with indication of the excavated Abbey of Boudelo (1). The dashed line represents the boundary between the palaeolake (to its south) and the coversand ridge (to its north). (b), Location of the studied area (red dot) within the late medieval County of Flanders (orange boundary) and the current state boundary of Belgium. Maps composed in ESRI ArcMAP 9.3.1. Full size image

More recent, natural processes (e.g. flooding) and modernisation have altered the cultural landscape of medieval Flanders, leaving the nature and exact layout of these designed landscapes largely unknown8. Although social formation and economic exploitation of reclaimed landscapes during the High Middle Ages is, to some extent, documented in historical and cartographical sources, archaeological evidence remains scarce. One of the main reasons for this scarcity is that traditional investigations have focused on recovering architectural remains rather than situating the structures within their broader environmental contexts. By focusing on elite residences and monastic buildings, archaeological investigations have contributed to the biased image of medieval settlement landscapes that still prevails.

The situation was no different for the Cistercian abbey of Boudelo located in the north of the County of Flanders (Fig. 1b). In 1197, a small religious community settled in this area9, which at that time was an outback of the County, dominated by marshes and wetlands. Early historical accounts, such as those by monks from the Abbey of Clairvaux in Bourgogne (France), give testament to the harsh environmental conditions. They describe life at Boudelo as pauper and misserimus: poor and full of misery10. However, the community improved its property by cultivating the surrounding land. Between the 13th and 16th centuries, the monastic estate expanded to over 1000 ha, making the community one of the leading cultivators in the County. After religious as well as military struggles and successive floods, the monks were forced to abandon their grounds in Boudelo in 1578. They found refuge in Ghent and the monastic buildings were sold and dismantled.

Although the extensive reclamation strategy of the abbey is attested in historical records mentioning embankment, drainage, stockbreeding, extraction of peat and clay and the production of building ceramics, it remains hidden in the archaeological record. Excavations in the 1970s revealed the remnants of the cloister range and the abbey church, leading archaeologists to interpret the abbey grounds as limited to the coversand ridge11 (Fig. 1a). The border of the monastic precinct was believed to coincide with the edge of a Late Glacial palaeolake, which was and remains, a waterlogged environment dominated by peat and lime-rich lacustrine deposits (Fig. 1, Supplementary Fig. 1–2). However, in 2011 an electromagnetic induction (EMI) survey of this wetland area drastically altered this interpretation, as it unveiled traces of the abbey's outer court that once was part of the monastic precinct; a previously unknown designed landscape from which the monks directed their cultivation of the surrounding area.