Born 13 December 1941 in Berlin, Professor for national public law and international public law at the law faculties of the Universities of Mainz (1982), Kiel (1982-1993) and Heidelberg (1993-2012); Director at the Max Planck Institute for Comparative Public Law and International Law, Heidelberg (1993-2012); Managing Director at the Max Planck Foundation for International Peace and the Rule of Law, Heidelberg (2013-2020). Vice-President of the German Research Foundation (1996-2002); Vice-President of the Max Planck Society for the Advancement of Sciences (2002-2006); Membre de l’Institut de Droit International (since 2007); Manley O. Hudson Medal, American Society of International Law, 2020.

Judicial experience
Judge at the International Tribunal for the Law of the Sea (1996-2017); re-elected in May 1999 and in June 2008; Vice-President (1996-1999), President (2005-2008);

Member of the International Environmental Board of Arbitration, The Hague (since 2001); Member of the Arbitration Panel on Antarctica (since 2017);

Member or Presiding Arbitrator or conciliator of several international arbitral tribunals or a conciliation commission:
Chagos Archipelago (Mauritius v. United Kingdom); South China Sea (Philippines v. China); Presiding Arbitrator of the Arbitral Tribunal concerning the delimitation of the Bay of Bengal (Bangladesh v. India); Member of the Conciliation Commission Timor-Leste/Australia (2016-2018); Presiding Arbitrator in the matter of Arbitration under the Agreements between the Government of the Republic of Finland and the Arab Republic of Egypt on the Promotion and Protection of Investments respectively dated 5 May 1980 and 3 March 2004 and the UNCITRAL Arbitration Rules 1976 (Bahgat v. Republic of Egypt); Presiding Arbitrator in the Dispute Fynerdale Holdings B.V v. Czech Republic; Arbitrator in the Dispute Concerning the Detention of Ukrainian Vessels, Ukraine v. Russia.

Publications
Numerous publications on general international law, United Nations law, human rights, the law of the sea, international trade law, environmental law and on international dispute settlement. Publications also on national and comparative public law, in particular constitutional law.