History of Modern International Law till the end of 18th century 

Authority of the Organized Church was beginning to be challenged as there were constant struggles between religious authorities and rulers known as Crusades (12th and 13th centuries). Introduction of Modern Printing in the 15th Century disseminated knowledge undermining feudalism. Renaissance – 15th Century Treaty of Tordesillas – 1493 – Between Isabella I of Castile, Ferdinand II of Aragon and John II, King of Portugal establishing a new boundary or demarcation line. Development of Concept of ‘Sovereignty’ by scholars like Bodin, Machiavelli, Hobbes etc. (15th and 16th centuries).Increase in the number of independent states led to formation of customary rules of International Law involving diplomatic relations. Earlier, International Law was called ‘Law of Nations’. Treaty of Amasya establishing peace – 1555 – Between Ottomans and Safavids after their war. International Law was influenced by Natural Law (Inherent Law or Higher Law based on God, Nature and Reason) (15th and 16th centuries). Important scholars like Vittoria, Belli, Brunus, Suarez, Gentilis were present during this period. Formation of Dutch East India Company – 1602 – Colonial Expansion. Establishment of lex mercatoria by Britain as international trade was increasing at a frantic pace. The greatest of the early writers is Hugo Grotius and is often called the father of International Law (16th and 17th centuries). De Jure Belli ac Pacis (1625) by Grotius dealt with actual customs that were followed by the states of the day. The concept of Freedom of Seas was also explained and put forth by Grotius through his work Mare Liberum (1609). Peace of Westphalia – 1648 – Two treaties signed in the Westphalian cities of Osnabruck and Munster ending the thirty years war that brought peace to the Holy Roman empire. Peace of Utrecht – 1715 – Series of treaties – Between Great Britian, France, Portugal and Spain for end of War of the Spanish Succession. 1758 – Scholar Emer De Vattel published the famous work of ‘The Law of Nations’. 4th July 1776 – US Declaration of Independence – Brought the concept of ‘self-determination’ to the world stage.