An interesting story on the "original Indiana Jones":

Like Jones, Rahn was an archaeologist, like him he fell foul of the Nazis and like him he was obsessed with finding the Holy Grail - the cup reputedly used to catch Christ's blood when he was crucified. But whereas Jones rode the Grail-train to box-office glory, Rahn's obsession ended up costing him his life.

However, Rahn is such a strange figure, and his story so bizarre, that simply seeing him as the unlikely progenitor of Indiana Jones is to do him a disservice. Here was a man who entered into a terrible Faustian pact: he was given every resource imaginable to realise his dream. There was just one catch: in return, he had to find something that - if it ever existed - had not been seen for almost 2,000 years.