Ambassador Valentin Zellweger is Head of the Permanent Mission of Switzerland to the United Nations Office and to the other international organizations in Geneva. Until the summer of 2016, he was Head of the Directorate of International Law and Legal Adviser to the Swiss Foreign Ministry. Zellweger started his professional career as a research assistant in international law at the University of Basel where he also submitted his doctoral thesis. Joining the Swiss Foreign Ministry in 1991, he has served as a diplomat in Kenya and as a legal adviser to the Swiss Mission to the United Nations in New York. He has represented Switzerland in different treaty negotiations and was a member of the Swiss delegation to the Rome Conference on the establishment of the International Criminal Court (ICC). Between 2003 and 2007, Zellweger served as Chef de Cabinet of the first President of the ICC in The Hague during the setting-up of the newly established Court.