The article illustrates the importance of business diplomacy practised by free agents, who navigated and negotiated between northern European empires for widespread commercial, legal and administrative developments. Abraham Cabiljau’s career is an example from the early modern Swedish empire, which stands on the threshold of a new era. In the Swedish empire, Cabiljau was involved in several different sectors, from military recruitment to the development of state accounting and administration of international trade. He represents the Swedish empire’s vast economic relationships with international merchant networks operating in a broad spectrum of military and commercial arenas. The Swedish empire was economically dependent on the financial resources of the merchants in Amsterdam, and economic prosperity was not the sole contribution of these merchants. The education, knowledge and connections provided by Cabiljau greatly enhanced the administration and organisation of Sweden’s international trade by importing a new legal mindset and organisational culture. In return, northern mining resources and Baltic commerce were alluring for Dutch merchants. We argue that the modelling of international organisations was an essential part of Swedish economic development. However, the first Swedish trading companies remained an experimental attempt to transplant the Dutch East India Company (VOC) model to Sweden. Individuals like Cabiljau represent key actors who ignited, taught and promoted commercial law development in Sweden, on which international commerce was later built upon, with long-lasting impacts.