The International court proposed at the beginning of the 20th century, to hear prize cases. An international agreement to create it, the Convention Relative to the Creation of an International Prize Court, was made at the Hague on October 18, 1907. The International Prize Court was to hear appeals from national courts concerning prize cases. It was later modified by the Additional Protocol to the Convention Relative to the Creation of an International Prize Court, done at the Hague on October 18, 1910. However, neither the convention nor the subsequent protocol ever entered into force, since none of the signatories ever ratified it, and the court never came into existence. The Convention was opposed, particularly by elements within the United States and the United Kingdom, as a violation of national sovereignty.