In 1886, to support its claims of effective occupation, France again assumed direct control of its West African coastal trading posts and embarked on an accelerated program of exploration in the interior. In 1887 Lieutenant Louis Gustave Binger began a two-year journey that traversed parts of Ivory Coast's interior. By the end of the journey, he had concluded four treaties establishing French protectorates in Ivory Coast. Also in 1887, Verdier's agent, Marcel Treich-Laplène, negotiated five additional agreements that extended French influence from the headwaters of the Niger River Basin through Ivory Coast.