The standout finding, published in the journal Nature, surrounded mutations in a gene called ERAP2.

If you had the right mutations you were 40% more likely to survive the plague.

"That's huge, it's a huge effect, it's a surprise to find something like that in the human genome," Professor Luis Barreiro, from the University of Chicago, told me.

The gene's job is to make the proteins that chop up invading microbes and show the fragments to the immune system, priming it more effectively to recognise and neutralise the foe.

The gene comes in different versions - those that work well and those that do nothing - and you get a copy from each parent.

So the lucky ones, who were most likely to survive, inherited a high-functioning version from mum and dad.

And the survivors had children and so passed those helpful mutations on so they suddenly became much more common.

"It's huge we see a 10% shift over two to three generations, it's the strongest selection event in humans to date," evolutionary geneticist Professor Hendrik Poinar, from McMaster University, told me.

The results were confirmed in modern day experiments using the plague bacterium - Yersinia pestis. Samples of blood from people with the helpful mutations were more able to resist the infection than those without.

"It's like watching the Black Death unfold in a petri-dish - that's eye-opening," said Prof Poinar.