Drawing on the works of Alexandrowicz and Grewe, this article intends to illustrate the relevance of colonialism to the evolution of present, universal international law. The central question addressed is as follows: Do we have to regard the exclusionist international law of the imperial era (culminating in the late 19th century) as an anomaly, or ‘accident’ in international relations and hence the achievement of universal participation half a century later as a ‘return to normalcy’, or was colonialism, alongside the law that governed it, a period of transition from international law as a genuinely European order to the universal order it is today? Alexandrowicz’s and Grewe’s answers to these questions appear to be diametrically opposed. More important than judging who of them is right is understanding why these scholars arrived at such diverging conclusions.