Following the manuscript's discovery in 1864, scholars have widely assumed that De Jure Praedae was written by the Dutch lawyer Hugo Grotius in the period 1604–1606. Yet the conventional dating fails to consider the materiality of Ms. BPL 917 in Leiden University Library. By analyzing paper supplies, this article throws new light on the date and manner of the manuscript's composition. The watermarks in the paper, the quire divisions and foliation are considered in combination with relevant textual evidence, such as (...) manuscript references to historical events and any allusions to Ms. BPL 917 in Grotius’ letters and other archival sources. This approach has yielded unforeseen results. Yes, Grotius wrote out the original text in 1604/05, as a fair copy of a previously existing work. Yet he did not stop there. Entire folio-pages were crossed out in Ms. BPL 917 and new ones inserted in the following sequence:- in, or shortly before, January 1607, Grotius deleted f. 63v and 67r and inserted f. 64–66- between January 1607 and Nov–Dec. 1608, he deleted f. 7v, 19r, 38v, and 43r-v and inserted f. 8–9, 18, and 39–42- in November–December 1608, he deleted f. 119r–122r and inserted f. 117–118.These revisions were a direct response to the challenges faced by the Dutch East India Company in this period. Its growing empire in Southeast Asia was under threat from the peace and truce negotiations between the States General and Philip III of Spain and Portugal. Grotius’ revisions of Ms. BPL 917, along with chapter twelve's appearance as Mare Liberum in April 1609, justified the continuation of Dutch empire-building in the East Indies, the Twelve Years’ Truce notwithstanding. Grotius’ rights and contract theories made it perfectly acceptable to conclude a peace or truce in Europe, yet persist in colonial warfare beyond the Line . In this respect – the differentiation between ‘the West and the rest’ in international relations – Grotius’ legacy is still with us today. (shrink)