When a ruler of the former ?Christian Republic? went to war, he had to inform his Christian enemy about the fact itself (declaration of war) and would give to him and to other Christian rulers reasons for this serious step (legitimisation of war). This concept was not Christian in its origin, but in the theological theory of Just War it became basic for the order among Christian states. Later it again transcended religious restrictions and became basic for warfare until today.It was, however, not the mere fact of secularisation that made the theory of Just War open for the future international order. Legitimisations of War changed substantially with the revolutions in communications since the 15th Century. The ?personal? declaration of war became less important, the legitimisation by war manifestos became crucial, i.e. official pamphlets that were written or drafted by rulers or high-ranked politicians. Manifestos were directed towards an international public. Their intention might have been in particular to convince other rulers, people of political influence, subjects that were affected by the war etc., but they argued that the reasons given for war in the individual case would be acceptable for the whole Christendom or even for all civilized societies and the whole ?world?. Thus they mirror the existing ideas of an international system and its values, as legitimisations of war make sense only if the author expects that there will be readers who can follow his argument. In the context of the project?s main subject and different panels it is e.g. most significant when Queen Anne of Great Britain in 1702 declared war on France for the ?liberty and balance of Europe?. This was the first time that a monarch used the idea of balance of power in a war legitimisation which shows that at that time it was a political standard that was acceptable to the European public.In my paper I would like to analyse main ideas of an international order given in war legitimisations from 16th to 18th Century. ..PAT.-Unpublished Manuscript [ABSTRACT FROM AUTHOR]