The decapitated heads displayed at Kurtz's station may have been inspired by an incident on the Stairs Expedition, part of Leopold's campaign to incorporate the kingdom of Katanga into the Congo Free State. Reaching the African king's compound at Bunkeya, Captain William Stairs records in his diary how the Europeans 'first recognized Msiri's headquarters by the skeletons fixed to stakes round one section of the village and by a terrible pyramid of human heads and amputated hands placed on a sort of pedestal table at the door of his dwelling,' and the sight of 'fresh human heads grimacing ... on the stakes in the village,' of which he 'counted one hundred of these frightful trophies.' When Msiri was killed by the expedition, the Europeans set the king’s own decapitated head upon a stake as a warning to potential rebels.
Another possible inspiration was the Belgian Force Publique officer Leon Rom. Kurtz's post is loosely based on Stanley Falls, where Rom was made station chief in 1895, five years after Conrad visited; Conrad may even have have met Rom while the latter was station chief at Leopoldville. A British explorer and journalist who passed through Stanley Falls in 1895 described the aftermath of a punitive military expedition against some African rebels: 'Many women and children were taken, and twenty-one heads were brought to the falls, and have been used by Captain Rom as a decoration round a flower-bed in front of his house!' This account first appeared in Century Magazine and was reproduced in The Saturday Review, a magazine Conrad admired and read faithfully.
Two other figures within the Congo Free State hierarchy may have served as partial models: Guillaume Van Kerckhoven, a Belgian Force Publique officer; and Léon Fiévez, commissioner of the Equator District. Van Kerckhoven informed the British consul Roger Casement that he paid his African soldiers ‘5 brass rods (2 ½ d.) per human head they brought him during the course of any military operations he conducted’ in order to ‘stimulate their prowess in the face of the enemy.’ Léon Fiévez, a much hated state official who terrorised a district 300 miles north of Stanley Pool, and whose excesses lead the Congolese to christen him 'the Devil of the Equator,' described his actions when surrounding villages failed to supply his troops with the fish and manioc he demanded:
I made war against them. One example was enough: a hundred heads cut off, and there have been plenty of supplies at the station ever since. My goal is ultimately humanitarian. I killed a hundred people ... but that allowed five hundred others to live.
At the time of Conrad's visit, Léon Fiévez had just taken command of the post of Basoko, a likely overnight stop for the Roi des Belges going both up and down the river.
Several other possible models have been suggested for Kurtz, including Leopold II, Henry Morton Stanley, Arthur Hoddister (a British ivory trader), Emin Pasha (whom Stanley attempted to relieve in Equatoria in 1887, and who was killed by Arabs in 1892), Edmund Barttelot (in charge of Stanley's rear guard during the Emin Pasha Relief Expedition), and Charles Henry Stokes (an Irish ivory trader summarily hanged by a Belgian officer in 1895). Kurtz has even been framed as an alter ego of Marlow, and by extension of Conrad himself.
However, just as ‘All Europe contributed to the making of Kurtz,' it is unlikely Conrad based Kurtz on any single individual.