Britain's interest in the Upper Guinea region declined with the end of the British slave trade in 1807 and became focused on Sierra Leone after the Boloma Island settlement was abandoned. At the start of the 19th century, the Portuguese felt reasonably secure in Bissau and regarded the neighboring coastline as their own. Their control was tenuous: for much of the 19th century the Portuguese presence in Guinea was mainly limited to the rivers of Guinea, the settlements of Bissau,
Cacheu and
Ziguinchor (the last now in Senegal). Elsewhere it was preserved, with little official assistance, by local
Creole people and
Cape Verde islanders, who owned small
plantations (Pontus). The existence of plantations run by the French and Senegalese brought a risk of French claims south of the
Casamance River. After the
Berlin Conference of 1885 introduced the principle of
effective occupation, negotiations with France led to the loss of the valuable
Casamance region to
French West Africa. In exchange, the French agreed to Portuguese Guinea's boundaries. 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 after 1884, Portugal might also have lost Bolama to Britain. However, Britain and Portugal agreed in 1868 to international arbitration. President
Ulysses S. Grant of the United States of America acted as arbiter, and in 1870 awarded the island to Portugal. Portugal's precarious financial position and military weakness threatened its ability to retain its colonies. In 1891,
António José Enes, Minister of Marine and Colonies, rationalized taxes and granted
concessions in Guinea, mainly to foreign companies, to increase its exports. The increased revenue was intended to fund a gradual expansion of control that would give Portugal tax revenue from trade and the indigenous people. The modest increase in government income between 1895 and 1910 did not cover the cost of the troops used to impose the taxes, however. Enes' policies largely failed; resistance continued in the interior, on the islands, and at the coast. However, once military occupation had begun, Portugal persisted, hoping for future benefits. After the Portuguese monarchy fell in 1910, the new republic set up a ministry for colonial administration. Guinea's income increased as peanut prices rose, tax collection improved and its budget showed a surplus. Between 1913 and 1915,
João Teixeira Pinto used
Askari troops to impose Portuguese rule and crush resistance to the
hut tax by destroying villages and seizing cattle, causing many to flee to Senegal or into the forests. The cost of maintaining his forces and the resulting
budget deficits led to his recall in 1915. Although the
First World War increased world demand for tropical products and stimulated Guinea's economy, a post-war slump, and frequent political crises created a deep
recession. By the
1926 military uprising in Portugal, most of Guinea was occupied, administered, and taxed, but its revenue was not enough to pay for its administration, much less to expand it. When the
Estado Novo imposed police on the
Bissagos Islands in 1935–36, it completed its control of Guinea. Between the 1930s and 1960s, the colony was a neglected backwater, whose only economic significance was to supply Portugal with about one-third of its vegetable oil, from
peanuts. It was unclear if its population of about 500,000 in 1950 was large enough to grow enough peanuts to pay for its imports and administration, and still grow food for its population. In 1951, because of anti-colonialist criticism in the
United Nations, the Portuguese government renamed all of Portugal's colonies, including Portuguese Guinea, as overseas provinces (
Províncias Ultramarines). Development was largely neglected before the start of the country's independence war. One paternalistic governor,
Sarmento Rodrigues, promised to develop agriculture, infrastructure, and health, but did little to fight the upsurge in
sleeping sickness in the 1940s and 1950s. Guinea saw little public investment in the first Portuguese Overseas Development Plan (1953–58), and a second plan (1959–64) concentrated on its towns. Adequate rural health clinics were not provided until General
Spínola's program of 1968–73. Public education provided was limited: in 1959 Guinea had some 200 primary schools with 13,500 pupils and 36 post-primary schools, mainly for the children of Portuguese citizens and urban
assimilados, with 1,300 pupils. These schools were never particularly accessible to native inhabitants, and only around nineteen percent of school-age children attended primary school. Literacy rates suffered, with an estimated 99 percent of the population illiterate in 1950, making Guinea the most illiterate Portuguese territory in Africa. ==Independence movement==