Tucked away on the second floor of Chicago’s Field Museum of Natural History is the Regenstein Pacific Laboratory. The 1,600 square foot facility, secreted within a massive collection of Pacific Coast artifacts, is open to the rest of the museum thanks to a bank of viewing windows.

That’s where several teenaged members of the Chicago Youth Symphony Orchestra, fresh off their morning performance in the museum’s main hall, stood with their noses pressed against the window. Inside, Field Museum staff member JP Brown, an avid player of video games, was taking a stroll through Assassin’s Creed Origins on a big screen television.

Outside the kids were absolutely loving it.

But Brown wasn’t there to rack up his kill count or hunt collectibles in-game. I’d invited him to join me for a closer look at Origins’ Discovery Tour mode, available for free to owners of that game on PC and consoles. With it players can take in the sights of ancient Egypt through 75 fully narrated and illustrated walking tours.

Brown isn’t just your average museum conservator. He has spent the better part of the last decade preserving the Field Museum’s collection of priceless mummies from around the world, including multiple samples from the Ptolemaic period — the same span of time brought to life in Origins. He’s also unlocked his fair share of achievements in Dishonored 2.

So did the developer Ubisoft get it right? Absolutely, said Brown... with a few caveats.

“I really like that they’ve done with this,” Brown said. “But I’m really struggling with how many of these things I would actually walk through.

“I enjoy this because I’m really interested in mummification and it’s always fascinating to me about what people think as opposed to what we know. As a museum, our job is to try and communicate what we’re finding out to people and to make the gap between what we understand and what the public knows as small as possible.”

In March, the Field Museum opened Mummies, an exhibit that features examples of the burial practice from both Egypt and Peru, some of which have not been on display since the 1920s. Brown was instrumental in applying computer tomography, better known as CT scanning, to those specimens for the first time. Thanks to his work, scientists were able to look inside those mummies without unwrapping them. What emerged was evidence of a very different kind of mummification ritual than the one depicted in Origins.

In the mummification tour shown in Origins, which you can find in multiple places on YouTube, Brown said that players are being shown an almost archaic form of the burial practice, one that given the time period would have been exceedingly rare.

Origins takes place during the late Ptolemaic period, around 49 to 47 BC. At the time, Egypt was seeing the rise of a true middle class and it wasn’t just the pharaohs who were interested in preserving their bodies for the afterlife.

“Over that period, let’s say from the Fourth Dynasty to the end of the Ptolemaic era which is what we’re looking at now in Assassin’s Creed, the mummification ritual changes a lot,” Brown said. “It’s a 4,000-year period, so obviously things do change as you go along. In this late Ptolemaic period it’s not typical for the organs to be taken out and put in canopic jars as we’re seeing here because there’s a lot more shared tombs.”

Just as in modern society, real estate was at a premium in ancient Egypt. Having your organs interred beside you in separate containers took up a lot of space. The Field’s specimens show that organs were still ritualistically removed from the body, but then they were re-inserted into the original cavities. Each was mummified separately, and wrapped in a bundle along with tiny figurines representing Egyptian deities. It was a much less expensive process that the one shown in Origins, and allowed for larger family units and even the members of commercial guilds to be buried in condo-like shared tombs.

“One of our challenges, looking at these CT scans, is to try and figure out what in the body cavity is organs — returned organs — and which organs there are,” Brown said. “Sometimes there seem to be more packets than just [the liver, lungs, intestines and stomach], and then other times there are fewer. And so you’re like, what on earth is going on there?”

Mummification was first described in an ancient text called An Account of Egypt written by Herodotus and, by and large, he got it mostly right. But there were other kinds of burial methods that were much more common during the Ptolemaic period.

“There’s a Rolls Royce-style of mummification,” Brown said, “which is what you get if you’re a pharaoh or a super-important court functionary. Those are rare and they’re fabulous, but they’re super expensive. Then there’s the Volvo in the condo tomb, which is what the kind of middle class gets, and that’s probably about 20 percent of the population or something like that. And then everyone else.

“The remaining 80 percent effectively get something really cheap and cheerful which is basically just opening the body cavity, flushing it out with turpentine, and then sticking them in the ground. So that’s more like the [Ford] Pinto. And the Pintos are sort of interesting because not many of them survive, but it’s what happens to most people.”

Mummification wasn’t only practiced in ancient Egypt. Much of Brown’s work for the Mummies exhibit focused on stabilizing Peruvian artifacts found in the Field Museum’s collection and making them ready for public display. That includes contextualizing them for a modern audience.

“The idea is that climate provides you the opportunity for doing this kind of mummification,” Brown said. “People don’t realize that the oldest tradition of mummification is actually South American and they were mummifying people about 5,000 BC. That tradition went right the way up to the arrival of the Spanish and the Portuguese. It’s a 6,500-year tradition — much longer than the Egyptian tradition, and it starts much earlier.

“It really takes a different turn in Peru. It’s much more egalitarian. Everyone gets roughly the same kind of mummification and you’re buried as a family group as individual bundles. And there’s some evidence that the bundles are brought out periodically, for what we really don’t know. Perhaps they’re family or political occasions. Maybe you want grandma to be at the funeral so you bring her mummy bundle out. People keep doing that, it gets more and more elaborate.

“When you get to the Incas, you’ve not just got the mummies of the Incas but a whole infrastructure of preserving them in much the same way that you have with the pharaohs in Egypt. So, it’s something that political importance becomes attached to them, but very very different approaches socially to how you mummify the dead.”

To prepare for the exhibit, the Field Museum’s mummies were first secured and made ready for transport downstairs and outside to a back lot. That’s where a massive CT scanner was set up. After the images were captured, Brown and his team set about rendering those scans in such a way that people could interact with them, slicing them away one tiny sliver at a time to look inside.

The difficulty, Brown said, was in finding the right kind of technology that would allow people to interact with those scans.

“We started off with this system that actually used an Xbox controller,” Brown said. “No one could figure out how to use it. Unless they were a 14-year-old gamer, no one could do it. It was the opposite of intuitive.

“Then we tried putting them on iPads and there was some interest. You had touch to zoom and all that. It was fun, but there were some interesting scaling problems. When you put a human mummy on an iPad it just feels like it’s the wrong scale. It’s too teeny weenie. And that was kind of a bummer because we spent a lot of effort doing that and then found out that it didn’t work, or that it just didn’t look good when you did it.”

What Brown ended up doing was coopting software that was developed in Sweden to perform non-invasive autopsies. They removed much of the program’s functionality, and then loaded it up onto a gaming PC driving a 70-inch touchscreen table.

“You’ve got the whole kind of pinch-to-zoom, you can strip layers off in one axis, you can bring a cut plane in so you can sort of see inside the mummy with all the layers in place, and I think it just looks extraordinary,” Brown said. “This is the real CT data, it’s absolutely what we got running the mummy through the scanner, and you get to play with it and see what there is there.”

The Mummies exhibit runs through April 21, 2019.