1. Periods of international law. 2. Pre-state period. 3. International law in ancient times. 4. Classical period of international law. 5. League of Nations as first universal international organisation. 6. United Nations. 7. Why is it difficult to render accurately a historical account of the origin of international law? 8. What should be the focus of any account of how and why international law began? 9 . Peculiarities of international law in the 20th century