peer reviewed ; The “Belle Epoque” saw the revival of the colonial idea in new forms. A second European colonization wave washed over Africa. King Leopold II unfolded his activities in Congo from 1876 onwards. There, his efforts to develop a so-called “philanthropic” enterprise soon evolved in a process of state formation, overshadowed by intrigues and tensions that were a consequence of colonial competition between the Western powers. Only a decade later, at the Berlin Conference of 1885, a definite arrangement was adopted. Everywhere in Europe, a disputed transition was made from liberal to more conservative ways of government. Of course this tension field also dominated intellectual life. There was an intense debate between partisans of colonialism and supporters of worldwide free trade. For the development of his colonial doctrine Leopold II had been inspired by intellectuals that supported economic expansionism. Most of them were active in the field of economic geography. But the King also searched for support in other academic circles and mobilized Emile de Laveleye (1822-1892), one of Europe’s brightest minds, to join him in his quest for the most adequate economic, social and political model of a future state in the heart of Africa. In his books, articles and pamphlets, the liberal minded political economist de Laveleye showed himself an unshakable opponent of colonization and imperialism. However, in the period 1875-1885 – a decade so crucial for Congo – a surprising intellectual rapprochement between de Laveleye and Leopold II was established. For a certain time, this competent man of science advised the King, putting into royal service an intellectual network of European range. This paper investigates how, in the complex and constantly evolving public discussion about Congo, two apparently opposing minds attracted each other. We focus on de Laveleye’s important pleas for a “neutral and international formula” that would place Leopold II in a conflicting situation with Portugal and France. This study ...