January, 1890 - Britain threatens Portugal with an Ultimatum: Abandon south-east Africa or face a naval bombardment of Lisbon.
Three centuries earlier, the poet Lu s de Cam es described the region at issue -
Behold the lake which is the Nile's source.
And the green Zambezi, too, begins its course.
Further upstream, the river becomes serpentine, twisting itself into a vast swamp, known to Europeans as Elephant Marsh,...