Gunnar Lagergren has performed many notable functions in the course of the twentieth century, most of which resulted in significant contributions to international law and, in particular, to the settlement of international disputes. As an arbitrator, he handled a number of important cases, including that between India and Pakistan concerning the Rann of Kutch and the Taba boundary arbitration between Egypt and Israel. He served with distinction on a number of important tribunals, including the European Court of Human Rights at Strasbourg and the Iran-United States Claims Tribunal at The Hague, where he was its first President.