The King also commissioned Lieutenant von Wissmann to complete his former work of discovery in the great district watered by the River Kasai and its affluents; and in and after 1886 he and his coadjutor, Dr. Wolf, greatly extended the knowledge of the southern and central parts of the Congo basin[457].  In the meantime the British missionaries, Rev. W.H.  Bentley and Rev. G. Grenfell, carried on explorations, especially on the River Ubangi, and in the lands between it and the Congo.  The part which missionaries have taken in the work of discovery and pacification entitles them to a high place in the records of equatorial exploration; and their influence has often been exerted beneficially on behalf of the natives.  We may add here that M. de Brazza did good work for the French tricolour in exploring the land north of the Congo and Ubangi rivers; he founded several stations, which were to develop into the great French Congo colony.

[Footnote 457:  H. von Wissmann, My Second Journey through Equatorial Africa, 1891.  Rev. W.H.  Bentley, Pioneering on the Congo, 2 vols.]

Meanwhile events had transpired in Europe which served to give stability to these undertakings.  The energy thrown into the exploration of the Congo basin soon awakened the jealousy of the Power which had long ago discovered the mouth of the great river and its adjacent coasts.  In the years 1883, 1884, Portugal put forward a claim to the overlordship of those districts on the ground of priority of discovery and settlement.  On all sides that claim was felt to be unreasonable.  The occupation of that territory by the Portuguese had been short-lived, and nearly all traces of it had disappeared, except at Kabinda and one or two points on the coast.  The fact that Diogo Cam and others had discovered the mouth of the Congo in the fifteenth century was a poor argument for closing to other peoples, three centuries later, the whole of the vast territory between that river and the mouth of the Zambesi.  These claims raised the problem of the Hinterland, that is, the ownership of the whole range of territory behind a coast line.  Furthermore, the Portuguese officials were notoriously inefficient and generally corrupt; while the customs system of that State was such as to fetter the activities of trade with shackles of a truly mediaeval type.

Over against these musty claims of Portugal there stood the offers of “The International Association of the Congo” to bring the blessings of free trade and civilisation to downtrodden millions of negroes, if only access were granted from the sea.  The contrast between the dull obscurantism of Lisbon and the benevolent intentions of Brussels struck the popular imagination.  At that time the eye of faith discerned in the King of the Belgians the ideal godfather of a noble undertaking, and great was the indignation when Portugal interfered with freedom of access to the sea at the mouth of the Congo.  Various matters