In order to narrow down the concrete content of an international due diligence standard, the third chapter starts with a brief historical summary of how due diligence obligations have entered the international stage. It retraces how the standard of due diligence has been developed in early scholarly writings before it was widely applied in the jurisprudence of so-called Claims Commissions in the context of alien protection laws. In spite of this early recognition, several codification attempts yet have failed which is why the standard of due diligence is not entailed in the ILC’s draft articles on state responsibility that mirror the modern status quo of the customary law on state responsibility. In a second step, chapter 3 therefore undertakes an attempt to locate the position of due diligence obligations in the existing law on state responsibility by comparing and contrasting the standard with other concepts of responsibility.