The most important antecedent of IHL is the current Armistice Agreement and Regularization of War, signed and ratified in 1820 between the authorities of the then Government of Great Colombia and the Chief of the Expeditionary Forces of the Spanish Crown, in the Venezuelan city of santa Ana de Trujillo.
At the same time, the involvement during the Crimean War of a number of such individuals as Florence Nightingale and Henry Dunant, a Genevese businessman who had worked with wounded soldiers at the Battle of Solferino, led to more systematic efforts to prevent the suffering of war victims.