This monopoly permitted Britain to resist French and German calls to internationalize trade on the Niger river during the negotiations at the 1884–1885 Berlin Conference on African colonization. Goldie himself attended the meetings and successfully argued for including the region of the NAC's operations within a British sphere of interest. Pledges from him and the British diplomats that free trade (or, in any case, non-discriminatory tariff rates) would be respected in their territory were dead letters: the NAC's over 400 treaties with local leaders obliged the natives to trade solely with or through the company's agents. Large tariffs and license fees eliminated competing firms from the area. The terms of these private contracts were made into general treaties by the British consuls, whose own treaties expressly incorporated them. Similarly, when King Jaja of Opobo organized his own trading network and even began running his own shipments of palm oil to Britain, he was lured onto a British warship and shipped into exile on Saint Vincent on charges of "treaty breaking" and "obstructing commerce".