Nigerian Journal of the Humanities 29 (September, 2024) 1-21 © 2024 Faculty of Arts, University of Benin, Benin City, Nigeria 1 TREATY DIPLOMACY IN PRE-COLONIAL NIGERIA: A CASE STUDY OF THE ESAN-BENIN TREATY OF UKOVEN Williams E. Orukpe  Abstract Literature on the politics, economics, militarism and the sociology of the Edoid peoples are aplenty. But there is a shortage of studies on their diplomatic practices. To bridge the gap, this study examines the Esan and Benin Treaty of Ukoven as a peace building mechanism in pre-colonial Nigeria. This treaty bears direct resemblance with modern treaties such as the Treaty of Locarno of 1925 and the Kellog-Brand Pact of 1928 in terms of purpose and utility. It contained and outlawed warfare in Esan and Benin suzerain relations. However, the specific objectives of this paper are to explore the basis for diplomatic studies in pre-colonial Africa; and to demonstrate the contribution of Esan and Benin to the evolution of diplomacy. It employed the historical research methodology to achieve these objectives. The secondary materials used in this study are interpreted using the qualitative analytical method. The findings of the paper are: the Treaty of Ukoven was a customary law that governed pre-colonial Esan-Benin relations. It was sealed by the planting of the “Ohimi Tree” in Esanland and the adoption of the “Ohimi Oath”. The study concludes that Esan commitment to the Ohimi Oath ensured that after it ceased to be a vassal of the Benin Kingdom in 1897; the spirit of the Treaty of Ukoven continued to shape Esan-Benin relations in colonial Nigeria and beyond. Keywords: Esan-Benin, Treaty of Ukoven, Diplomacy, Pre-Colonial Nigeria 1. Introduction Early treaties in Africa and elsewhere were forerunners to the Vienna Convention of Diplomatic Relations. This treaty signed in 1961 was the icing on the cake for the practice of diplomacy. The  Lecturer in the Department of History and International Studies, University of Benin. Email: williams.orukpe@uniben.edu