1. Antiquity and custom: just-war theory's childhood (Augustine; the bellum justum tradition) and the warrior codes (chivalry, the Hindu dharmayuddha, Islamic siyar);
2. The classical age of restraint (Grotius to the Hague): Grotius's De Jure Belli ac Pacis (1625) — war's law in bello; the Peace of Westphalia's system; the Lieber Code (1863) — the first modern war manual (the American Civil War's rules for armies in the field);
3. The Hague era (1899, 1907): the Conventions' codification — the laws and customs of war on land: the means-and-methods rules, the combatant categories, the Martens Clause ("until a more complete code... the dictates of public conscience") — and the Permanent Court of Arbitration;
4. The Geneva tradition (1864 → 1949): the Red Cross's founding (Dunant at Solferino, 1859) — the wounded's protection; the 1949 four Geneva Conventions (Unit 7's core) + the 1977 Additional Protocols;
5. The League era (1919–39): the Covenant of the League (collective security's first design — gaps and all) and the Kellogg-Briand Pact (1928) — the renunciation of war as an instrument of national policy (the outlawry's text, its Nuremberg vindication);
6. The Charter era (1945– ): the UN Charter's force-prohibition (Article 2(4)) — the modern jus contra bellum; the Nuremberg/Tokyo precedent (aggressive war as the supreme international crime); the ICJ's Nicaragua (1986) and the nuclear-weapons Advisory Opinion (1996); the Kampala aggression-definition (2010) and the Rome Statute's activation (2018) — the full circle from outlawry to individual criminal liability.