PhD Defence Posthumus alumnus Arnoud Jensen

On 12 February 2026, Posthumus alumnus Arnoud Jensen will defend his PhD thesis ‘Boeren als rentmeesters: Pacht tussen winst, macht en natuur in de Lage Landen, 1200-1400’ [transl.: ‘Peasants into Stewards: Leasehold between profit, power and nature in the Low Countries, 1200-1400’] at the University of Antwerp. Supervisors are Professor Tim Soens (university of Antwerp) and Professor Thijs Lambrecht (Ghent University).

Arnoud’s research examined short-term leasing in the Low Countries between 1200 and 1400. From the thirteenth century onward, leasehold became the dominant form of land management, and it is usually associated with profit maximisation and risk management. This study also highlights its role in sustainable management of natural resources by linking medieval leasing practices to the modern concept of environmental stewardship, understood as the responsible management of natural resources by temporary users.

Lease contracts contained a wide range of clauses regulating land use and natural resources. By analysing these provisions, the research investigated how profit-seeking, risk mitigation, and environmental management interact within leasing systems across five regions: Inland Flanders, Coastal Flanders, Artois–Cambrésis, Liège, and the Dutch River Area.

The findings contribute to four debates. First, the research suggests that leasing emerged earlier than previously assumed, with private individuals also active on the lease market quite early. Second, lease prices revise our understanding of the Late Medieval crisis: with new insights into the impact and timeline of the crisis. Third, the contracts reveal how profit-seeking, risk mitigation, and environmental management were structurally intertwined. Fourth, leasing had a clear ecological dimension, as contracts could encourage sustainable land use, even if primarily driven by non-ecological interests of lessors. Finally, the study reflects on the contemporary ecological crisis and modern lease legislation. Medieval contracts demonstrate that legal frameworks can promote responsible engagement with natural resources. Today, however, such a framework is largely absent, resulting in the underutilisation of leasing as an instrument for maintaining soil quality.

The N.W. Posthumus Institute wishes Arnoud a successful defence!