A Chi Rho is chiseled into the rock at Sunset Overlook in the Big South Fork National River & Recreation Area. (Ben Garrett/IH)

On a rock outcropping overlooking the Big South Fork River east of Oneida is an elaborate carving that at least closely resembles an early Greek symbol of Jesus Christ.

But how did it get there? And by whom? When?

Those are questions that don’t seem to have answers — even in a national park where just about any natural or manmade landform, structure or remains that can be studied has been.

The carving, is located at Sunset Overlook, which is not far from East Rim Overlook near park headquarters outside Oneida. No one can say for certain what the carving is supposed to represent, but it looks remarkably like the Chi Rho, an early christogram that dates back to ancient Greek culture.

The Chi Rho is made by superimposing the first two letters of the Greek alphabet — chi and rho, which look very much like the X and P in the English alphabet. Chi and rho are the first two letters for the Greek word ΧΡΙΣΤΟΣ, which is Christos — the Greek word for Christ.

While the Chi Rho has long been a symbol of Christianity, it actually predates Christ. In pre-Christian times, the Chi Rho symbol was used to denote passages of text in the margin of a page of manuscripts. Additionally, while the chi and rho are Greek letters, the Chi Rho symbol is most often associated with Latin, where it is used to signify Christ nouns.

The history of the Chi Rho is a fascinating one. According to the Latin historian Lactantius, who served as tutor to the son of the Roman emperor Constantine the Great, Jesus was said to have appeared in a dream to Constantine, ordering him to put a “heavenly divine symbol” on the shields of his soldiers. That symbol was the Chi Rho. One day later, Constantine’s army won the Battle of Milvian Bridge, which began Constantine’s conversion to Christianity. One year later, he confirmed his Christian beliefs in the Edict of Milan, and later eased the persecution of Christians in the Roman Empire. Eventually, the Chi Rho became part of the Roman Empire’s official insignia and the empire’s coins were emblazoned with the symbol.

No one is suggesting that the symbol at Sunset dates back to the times of the ancient Romans, of course. It was well over 1,000 years after Constantine that the first white men — who would have carried Roman culture across the ocean — arrived in North America, and several hundred years still before the northern Cumberland Plateau region was explored by non-Native Americans.

Most who have seen it, though, are in agreement that the symbol engraved into the rock at Sunset is a Chi Rho. But the question remains: who engraved it, and when?

As Ron Cornelius said in a Flickr photo of the rock carving, the carving at Sunset is “not typical graffiti.” Chiseling into stone is not an easy task, and the symbol on the rock outcropping is almost perfectly carved. It is thought that the carving predates the national park; its edges are smooth from years of weathering by the rain and wind, indicating that it has been there a while.

But just how long is a matter of question. Some who are familiar with the Sunset Overlook trail say that the carving is a relatively recent one. And while the symbol is well-weathered by years of wind and rain, it is chiseled into sandstone, which is a relatively soft rock that weathers more quickly.

One clue to the symbol’s age may be “Hiking the Big South Fork,” the book that former BSF ranger Howard R. Duncan co-authored with Brenda Deaver and Jo Anna Smith. The book is a virtual bible of the BSF’s hiking trails, packed with tidbits of information about each point of interest along each trail. But it does not mention the Chi Rho at Sunset. The book was originally published in 1989.

There is no history of settlement near the rock outcropping that is Sunset Overlook. The ridge leading to the edge of the gorge was heavily logged in the years predating the national park’s establishment; today, that ridge is criss-crossed by the scars of old logging roads. Further up the ridge, near present-day S.R. 297, the land was settled by farmers. Some of the more modern farm houses are utilized for management of the BSF, and remnants of the old farms can be seen near the start of the Sunset Overlook Trail, the 1.3-mile hiking trail that leads to the overlook.

As overlooks of the Big South Fork go, Sunset is unspectacular. Trees that grow from the base of the cliff line crowd the view of the river; by contrast, the East Rim Overlook further downstream, and the unofficial O&W Overlook further upstream, provide spectacular views of the river itself. From the overlook, though, you can see a small valley emptying into the river to the left — that is North White Oak Creek. Downstream, you can see the Leatherwood Ford bridge at S.R. 297. And, if you look closely, you can just make out the observation platform at East Rim Overlook. The large drainage between Sunset and East Rim is the location of Devils Cave, the largest slot cave in Tennessee. The hike to the overlook, which begins at East Rim Trailhead, is level and one of the easiest hikes in the national park.

This article is the June 2017 installment of "Our Back Yard," presented monthly on the first week of the month by First National Bank of Oneida as part of the Independent Herald's "Back Page Features" series.