As will be pointed out in Chapter VIII, one of the five conditions of international liability is an act on the part of a State, or more accurately: an act imputable to a State, which means that the act causing damage to a foreigner must have been an act for which the defendant State can be held responsible; it must be possible to impute the act to that State. The question then is: what are the acts for which a State must bear responsibility towards its sister States? The answer generally given is: that a State is responsible when a person authorized to act for the State, was acting on its behalf, when committing the act. In other words: the person must: a. be an official, an agent, of the defendant state, and b. in the particular case have acted in that capacity. The question as to how far a third condition must be fulfilled before the State is held accountable, viz. that the official must have acted within his competency, will receive consideration further on, in connection with the claim of Thomas Youmans1).