Spain, whose world empire inspired a golden age of economic and intellectual development in the sixteenth and seventeenth centuries, made an important contribution to international law. Francisco de Vitoria (1486-1546), who dealt with Spain`s treatment of indigenous peoples, invoked the law of nations as the basis for their dignity and innate rights and expressed an early version of sovereign equality among peoples. Francisco Suárez (1548-1617) emphasized that international law was based on the law of nature. A treaty is a formal and explicit written agreement by which states are legally united.  A treaty is an official document that expresses that agreement in terms of words; It is also the objective result of a ceremonial occasion that recognizes the parties and their defined relationships. The publication of a contract does not require academic accreditation or interprofessional contextual knowledge. Treaties are commonly referred to as « agreements », « conventions », « protocols » or « alliances » and, more rarely, « exchange of letters ». Often, « declarations » are adopted by the UN General Assembly. Declarations are not treaties, as they are not supposed to be binding, but they can be part of a process that ultimately leads to the negotiation of a UN treaty. Declarations can also be used to support the interpretation of treaties. The origins of international law date back to antiquity. Early examples include the peace agreements between the Mesopotamian city-states of Lagash and Umma (about 2100 BC) and an agreement between the Egyptian pharaoh Ramses II and the Egyptian king Hattouilis III, concluded in 1258 BC. Intergovernmental pacts and agreements of various kinds have also been negotiated and concluded by communities around the world, from the Eastern Mediterranean to East Asia.
At the same time, in the Islamic world, foreign relations were guided on the basis of dividing the world into three categories: Dar al-Islam (territory of Islam), where Islamic law prevailed; dar al-sulh (treaty territory), non-Islamic empires that have concluded a ceasefire with a Muslim government; and dar al-harb (war zone), non-Islamic countries, whose leaders are called upon to accept Islam.   Under the early caliphate of the seventh century, Islamic legal principles relating to military behavior and the treatment of prisoners of war served as precursors of modern international humanitarian law. . . .