The ECSQARU conferences originated from a European project — an ESPRIT Basic Research Action called DRUMS (Defeasible Reasoning and Uncertainty Management Systems) — led in the late 1980s by Philippe Smets (1938–2005) of the Free University of Brussels. The acronym, originally ECSQAU (proposed by H. Prade), echoed the French name of a river that flows through western Belgium. The “R” was added for the second edition of the conference to emphasize the interest in reasoning.

Another legacy of DRUMS (and its expanded sequel DRUMS-2) is the Handbook of DefeasibleReasoning and Uncertainty Management Systems, the series of which was edited by Dov M. Gabbay and Philippe Smets, and published by Kluwer between 1998 and 2002: vol. 1. Quantified representation of uncertainty and imprecision / edited by Philippe Smets; vol. 2. Reasoning with actual and potential contradictions / edited by Philippe Besnard and Anthony Hunter; vol. 3. Belief change / edited by Didier Dubois and Henri Prade; vol. 4. Abductive reasoning and uncertainty management systems / edited by Dov M. Gabbay and Rudolf Kruse; vol. 5. Algorithms for Uncertainty and Defeasible Reasoning / edited by Jürg Kohlas and Serafin Moral; vol. 6. Dynamics and Management of Reasoning Processes / edited by J.-J. Ch. Meyer and J. Treur; vol. 7. Agent-based defeasible control in dynamic environments / edited by J.-J. Ch. Meyer and J. Treur.

It should also be mentioned that while all the conferences were successful, one of them, the 2001 edition in Toulouse, was severely disrupted by an explosion at the AZF factory (French acronym for AZote Fertilisant, meaning nitrogen fertilizer) in Toulouse, on September 21, 2001, at 10:17 a.m., on the third day of the conference. Fortunately, only a few participants (including Philippe Smets) were slightly injured by glass shards from broken windows.

Past members of the steering committee include Salem Benferhat (Lens, France), Philippe Besnard (Toulouse, France), Didier Dubois (Toulouse, France), Finn Verner Jensen (Aalborg, Denmark), Jürg Kohlas (Fribourg, Switzerland), Rudolf Kruse (Magdeburg, Germany), Seraf’in Moral (Granada, Spain), Henri Prade (Toulouse, France), Romano Scozzafava (Roma, Italy).