As far as we can tell the islands were uninhabited when they were discovered on St Thomas's Day 21 Dec 1471 and St Anthony's Day 17 Jan 1472 by Portuguese explorers. For context, this is 20 years before Columbus sailed the ocean blue in 14 hundred and 92. Volcanic islands look terrible barren when they burst from the sea but the new rock is inherently richer than depleted rocks of, say, much of Australia and South Africa. Anything with red soils in Geoguessr seems to be located in one of those places. STeP became an early exporter of sugar until its trade was eclipsed by the islands of the West Indies. Under the Portuguese, the islands were subdivided into extensive roças [latifúndios / plantations / estates] owned by capitalists and worked by
Oddly, STeP is bracketted by the islands of Annobón and Bioko [formerly Fernando Pó] which are part of the same volcanic chain and were formerly Portuguese but were ceded to Spain by the Treaty of El Pardo in 1778 which tidied up a lot of disputes and violations of the Treaty of Tordesillas1494. That pope-mediated agreement divided the whole world between Spain and Portugal without troubling to ask France, England or the Netherlands, let alone the people already living there. Annobón and Bioko are now part of Equatorial Guinea, formerly Territorios Españoles del Golfo de Guinea, which had such interesting stamps when I was a kid.
At the moment STeP is reasonably democratic, left-of-centre, and stable. That may all change if they start to exploit off-shore oil-reserves. The corrupting power of oil has managed to turn Nigeria into a deeply divided and unhappy country. For today at least, let's party on for São Tomé and Príncipe.