At this time, Portugal occupied half a dozen coastal or river bases, controlling some maritime trade, but not much of the population. However, in 1892, Portugal made Guinea a separate military district to promote its occupation. Had the doctrine of Effective Occupation been as prominent in 1870 as it was after 1884, Portugal might also have lost Bolama to Britain. However, Britain and Portugal agreed to international arbitration in 1868. President Ulysses S. Grant of the United States of America acted as arbiter, and in 1870 he awarded the island to Portugal.