Upon entering the Under Gallery the Doctor is so distracted by acquiring a new fez that he fails to notice a painting depicting cybermen. While he might have walked right past it, the day will never come that I will ignore such a interesting background detail.
The painting is clearly modelled on ‘The Raft of Medusa’ by Théodore Géricault in 1818 to 1819. The original depicts survivors of a shipwreck that occurred in 1816. The similarity between the two would indicate that within the Doctor Who universe that this was produced by the same artist (and either this is the original painting which Théodore was forced to repaint or ‘The Raft of Medusa’ doesn’t exist in this universe.)
The shipwreck occurred when the French frigate Méduse overtook three other ships in its convoy in attempt to make good time but ended up going off course by 100 miles and ran aground.
The ship held 400 people but only enough boats to hold 250. Around 146 men and one woman were forced to board a hastily assembled raft. They spent 13 days, parched, starving and driven to madness and cannibalism. A harrowing occurrence to be sure.
Géricault didn’t experience these events first hand but was so intrigued he set out to speak with those who survived. His research extended to studying dead bodies and having a detailed scale model of the raft built. It is clear that his painting was intended to capture the truth of what happened.
The version of ‘The Raft of Medusa’ puts the cybermen in place of the survivors. Their design suggests that they are the most recent version depicted in ‘Nightmare in Silver’. Just how did they end up in the 19th century in this pitiful position?
The only possible answer is time travel. This could be via the void (similar to the events of ‘The Next Doctor’), through their own time travel technology or possibly by stowing away on a TARDIS (their cybermites seem small enough to escape detection and capable upgrading people in the past).
Their presence on the ship could simply be one of opportunity (this is where their journey through time brought them) or it could be deliberate. The frigate was on its way to accept the British return of Senegal, with the French appointed governor on board.
The cybermen could have been there to disrupt this historic event (but making history occur much as it did in our reality) by preventing the Méduse from reaching its destination.
The blame for the ship running aground was placed upon it’s captain, Viscount Hugues Duroy de Chaumerey. Although lacking in sailing experience he’d been given the position due to politics.
It could be that other factors were actually responsible, such as having cybermen onboard. If the raft in the painting does depict roughly 147 cybermen then it could be that they were converted from amongst the 400 members of crew.
This could be the source of a tense game, with the PCs on the ship as a mysterious illness sweeps through those on board and people start to go missing (difficult on such a cramped ship). They discover that there aren’t rats on the ship spreading a plague but cybermats and cybermites.
The cybermen could take the ship deck by deck, adding more people to their numbers. Given how advanced these versions are there would be little to defeat them and desperate measures could be taken.
The ship captain could have deliberately had the ship run aground in the hopes of sending the cybermen to the bottom of the ocean. Little did he anticipate that the cybermen would be able to build a raft in time to affect an escape. Alternatively in the chaos of the cybermen attack the ship just went off course and crashed.
Were all those upon the raft cybermen or were there those left unconverted? This would be a very tense situation, akin to sharing a boat with a hungry tiger as shown in ‘Life of Pi’.
In this version of events the cannibalism attributed to the survivors could actually be reference to the cyber conversions or possibly the cybermen turning on each other to salvage parts to make sure that at least some of them survive (their main motivation).
If the painting is an accurate representation the cybermen are in a dire situation. This can be an interesting situation as the PCs might be able to speak to them without fear, since they are so close to dying. Defeat by the elements would the cybermen realise the error of their ways or would they be defiant to the end?
By the time the survivors of the raft were picked up by the ship Argus only 15 were left alive. That is still enough for the cybermen to be a danger. Would that be enough to pose a threat or would the crew of the Argus be able to defeat the weakened aliens?
Were all the cybermen lost at sea or was there a cover up? In either case the PCs could explore 19th century France to recover and eliminate any remaining evidence of the cyber invasion.
An adventure could centre on Théodore Géricault. The PCs could join the artist who sets out to produce a painting of survivors of a ship wreck only to discover that metal giants were involved.
If there was a coverup there could be forces who work against Théodore to prevent the truth from getting out. The PCs could protect him to ensure that his work is completed, at least so that the Under Gallery can come and put it safely away.
Géricault made a choice to paint an actual event that was considered a national embarrassment. He may have refused to hide the truth or paint something he knew was a lie.
In which case, if ‘The Raft of Medusa’ does exist in the Doctor Who universe, a forger would need to copy his style to provide the sanitised version of events. The same forger might have done other paintings and PCs might eventually recognise his style, putting them on the trail of other famous paintings they realise how been similarly sanitised.
You can explore both angles (the events on the ship and the production of the painting) by having the PCs discover that they were also present on the Méduse and must travel back to 1816 to ensure that the cybermen don’t succeed in their plan.
This is just one example of how you can take an actual painting and create an adventure by introducing aliens into the subject matter. This is even easier if the painting depicts an historic event.