Admiral Cornelis Matelieff de Jonge, a Director in the Rotterdam chamber of the Dutch East Indies Company (VOC) for three decades during the early 17th Century, set sail from the Dutch Republic in 1605. He launched an attack on Portuguese Melaka in 1606 and signed landmark treaties with the rulers of Johor (1606) and Ternate (1607). After his return to the Netherlands in the autumn of 1608 he wrote a series of epistolary reports and memoranda that were carefully studied by leading policy makers in the Republic, among them the renowned jurist Hugo Grotius, and Johan van Oldenbarnevelt. These materials contributed to the formulation of early VOC policy for the Southeast Asian region in the period 1605‒20, and they yield candid insights into key issues of trade, security and the diplomacy of regional polities and their relations with Spain and Portugal. Here translated into English for the first time, this collection of treaties, reports and excerpts from Matelieff's travelogue will be of great interest to students of Southeast Asian and early colonial history and of the history of international law.