International humanitarian law has its origins in the customary practices of armies as they developed over the ages and on all continents. The “laws and customs of war”, as this branch of international law has traditionally been called, was not applied by all armies, and not necessarily vis-à-vis all enemies, nor were all the rules the same. However, the pattern that could typically be found was restraint of behaviour vis-à-vis combatants and civilians, primarily based on the concept of the soldier’s honour. The content of the rules generally included the prohibition of behaviour that was considered unnecessarily cruel or dishonourable, and was not only developed by the armies themselves, but was also influenced by the writings of religious leaders. This is a detailed factsheet about rule 55 on access for humanitarian relief to civilians in need.