This file photo shows the world's oldest complete copy of the Ten Commandments, written on one of the Dead Sea Scrolls in Jerusalem. The manuscript is on rare display at Israel's national museum in an exhibit of objects from pivotal moments in the history of civilization. (Dan Balilty/AP)

One of the earliest known copies of the Ten Commandments was written in soot on a strip of goatskin found among the trove of biblical material known as the Dead Sea Scrolls, widely considered to be one of the great archaeological finds of the 20th century.

Penned on parchment by an unknown scribe more than 2,000 years ago, the scroll fragment is one of humanity’s most precious documents — and so fragile that its custodians rarely permit it to be moved from the secure vault where it rests in complete darkness.

But for 14 days over the next seven months, the Ten Commandments scroll, known to scholars as 4Q41, will make a rare public appearance at the Israel Museum as part of a new exhibit called “A Brief History of Humankind,” a show based on the international best-selling book by Israeli polymath Yuval Noah Harari.

The exhibit chronicles humanity’s narrative arc by pairing cutting-edge modern art from the museum’s extensive collection alongside the display of 14 artifacts: the earliest-dated stone tools; the earliest evidence of man-made fire; the earliest known evidence of a family burial; the world’s oldest complete sickle — plus the Ten Commandments. It ends with Albert Einstein’s handwritten 1912 manuscript for the Special Theory of Relativity, including the formula E=mc 2 .

Even if you consider a couple of the commandments — maybe the ones about coveting? — as more suggestions than rules, seeing the scroll provides a major wow, taking us as far back as we can get to Moses the lawgiver, who faith and tradition say brought God’s orders down from Mount Sinai to his people.

Albert Einstein’s handwritten 1912 manuscript for the Special Theory of Relativity is on display as well. (Israel Museum)

As for who penned the copy of the commandments now on display at the Israel Museum, deep mysteries still remain. Were they inked by scribes belonging to a collective of celibate Jews from the sect known as the Essenes, who might have hidden the scrolls in the nearby caves? Or were the caves just a temporary place to cache documents as the Romans and Jews went to war?

For the opening of the exhibit earlier this month, staged to celebrate the Israel Museum’s 50th anniversary, more than 12,000 guests showed up — breaking a one-day record at the hilltop art and archaeology institution.

“No matter how many times I have heard the story of the Dead Sea Scrolls it still amazes me that these fragments survived,” said Tania Coen-Uzzielli, head of Curatorial Affairs at the Israel Museum.

A kid with enough Hebrew to make his bar mitzvah can still read the text: “Honor your father and mother so you will have a long and healthy life.”

The scrolls were discovered in a series of caves in the late 1940s and early 1950s by Bedouin shepherds. The Ten Commandments fragment was found in the famous Cave 4 not far from the Qumran ruins in the Judean Desert of the West Bank, where the scrolls had rested, undisturbed and preserved for two millennia, in darkness and dry desert air.

After the discovery, all sorts of crazy things happened to the scrolls. With enough twists and turns for an Indiana Jones sequel, they were lost and recovered, hoarded by secretive scholars, the subject of academic feuds, lawsuits and conspiracy theories and, very sadly, woefully mishandled. The delicate bits were flattened under glass panes in rooms without climate or humidity control.

As hard as it is to believe today, some of the fragments were taped together soon after their discovery, as researchers tried to piece the puzzle of the fragments back together. The conservators are still working to ever-so gently remove bits of yellowed, sticky cellophane.

The world’s oldest complete sickle is also part of the Israel Museum’s exhibit. (Israel Museum)

The curators at the Israel Antiquities Authority, which maintains labs at the Israel Museum, allowed a Washington Post correspondent a glimpse at how the scrolls are stored, protected and handled today. The ground rules were simple: Look, but do not even think of touching. If you could stop sweating and breathing (which creates subtle changes in temperature and humidity), probably better. And no photographs, and never tell a soul where the scrolls are stored, except to say, “deep in the bowels of the Israel Museum.”

The Ten Commandments fragment measures about 14 by 4 inches, and when it is not being readied for display it is sleeping between pieces of delicate tissue paper and acid-free cardboard in a simple archival box on a shelf in a secure vault that maintains “very strict” conditions — a rock-steady temperature of 68 degrees and 48 percent humidity in complete darkness.

“Literally resting,” as Pnina Shor, curator and head of the Dead Sea Scrolls Projects explained, “because the parchments are organic material — they need air to breathe.”

Israeli curators have decided it can be exposed to the light of a museum display case no more two weeks every five years.

In all, the Dead Sea Scrolls contain some 900 manuscripts composed of a few complete scrolls and tens of thousands of fragments. The works include books of the Old Testament or Hebrew Bible, as well as texts of particular significance to Catholics [such as the Book of Tobit and the Wisdom of Sirach], as well as commentaries, hymns, prayers and mystical formulas.

Some of the scrolls were rolled and wrapped in linen and stored in jars in the caves — part of a library or an archive?

Shor said that all the fragments in Cave 4 were found in a jumble on the floor, which suggests to some scholars that this specific cavern may not have housed a library but a genizah, a repository where Jews store worn-out and damaged religious texts, because it is forbidden to throw away writings containing the name of God (until they may be gathered up and buried following proper ritual).

Based on the style of the ancient writing, the Ten Commandments scroll is believed to have been penned in the 1st century B.C. The parchment is animal skin, most likely goat (other scrolls are sheep or deer). The ink is made from soot and was placed on it by a sharp quill. Other fragments have been dated by radiocarbon techniques and the DNA of the parchment examined, but the Ten Commandments scroll has not because the tests require the curators to clip off a tiny piece or two, which they are loath to do.

After the Ten Commandments went on display at the opening of the exhibit, the curators quickly detected that the humidity had climbed to 51 percent (just 1 percent above their red line), likely because the throngs of visitors, by simply breathing, had raised the moisture in the air.

Curators brought the scroll back down to the basement to rest again until the conditions in the exhibit could be adjusted. They promise the scroll will make another appearance very soon.