Ron Tappy became a committed Christian in his mid-20s, after deciding to read the Bible straight through.

When he did, "the Old Testament just floored me, and the history of Israel became my history, and I became a Christian in that process. To this day, I have an abiding respect for the texts of Scripture," he said.

It seems fitting, then, that Dr. Tappy's most famous discovery as a biblical archaeologist is a 38-pound limestone rock inscribed with a 2,900-year-old alphabet.

The stone was found two years ago at Tel Zayit in Israel, a dig about 25 miles southwest of Jerusalem. Using distinctive pottery and carbon dating of the soil levels above it, the stone was firmly traced to the 10th century B.C., the time when the biblical King Solomon was supposed to have lived.

The discovery was described by some experts as the most important find in biblical archaeology in the last 10 years.

One reason for the buzz was that the stone suggests the earliest Hebrew Scriptures could have been written down in that era -- hundreds of years earlier than many scholars had believed.

For Dr. Tappy, the alphabet stone also suggests not only that King Solomon was a real historical figure, but that he did in fact have a growing kingdom at the time, because Tel Zayit sits on the border of Solomon's Judah and the kingdom of Philistia, where the Philistines lived.

In fact, Tel Zayit is quite close to Timnah, the ancient city where the biblical strongman Samson is said to have married a Philistine woman.

While some have suggested the alphabet stone might have been used to train scribes, Dr. Tappy, the G. Albert Shoemaker professor of Bible and archaeology at Pittsburgh Theological Seminary, favors another theory.

The stone was part of a wall when it was found, he said, and "I do know that within a reasonable period of time after this period, the ancients believed the alphabet itself had power."

Since Tel Zayit probably sat on the edge of Solomon's kingdom, Dr. Tappy said, it's possible the stone was built into the wall of the city as mystical protection against Judah's enemies.

"I think the stone bespeaks an attempt to establish a presence in that part of the region, and if already the ancients were thinking of the alphabet as having magical powers to ward off evil, that may be another good reason to have it down there on the border."

The discovery of the stone has become one more piece of evidence in the vigorous and sometimes vitriolic debate among archaeologists over when the stories in the Bible were first written down and how historically accurate they are.

Most biblical scholars agree that the earliest Scriptures were not written down until many centuries after the eras associated with the patriarchs, the exodus and the occupation of Canaan.

But they are sharply divided over when that writing occurred and how much of the Old Testament may be based on real historical events.

One group, led by scholars like Thomas Thompson of the University of Copenhagen, doesn't believe the Scriptures were written down until a couple of centuries before the birth of Christ, and that most of the Old Testament stories are literary fabrications, Dr. Tappy said.

In the last six years, Israeli archaeologist Israel Finkelstein and Belgian expert Neil Silberman have written two books contending that most of the Old Testament was written during the reign of King Josiah of Judah in the seventh century B.C., and that many of the biblical stories of such figures as Abraham, Isaac, Jacob, Moses and Joshua contain places and people from Josiah's time.

Dr. Tappy puts himself among traditional archaeologists who believe that many scriptural tales are based on real historic events and places, but have been embellished or reshaped to serve a theological purpose.

The goal of the biblical writers, he said he believes, "is to explain history in the light of who God is and what God wants, so ultimately it's a theological work we have here."

"When the writers use historical details, that detail is not the point for them; the point is: What is God's nature, and what is our nature?"

Archaeology, he added, "can comment on the historical details scattered throughout the biblical texts, but it is less capable of confirming the meaning of those texts."

Take King Solomon, for example.

Dr. Tappy believes Solomon was a real ruler, but "I think the description we have of his kingdom in the Bible has probably been embellished. These Biblical writers were writing later and they're looking back on a golden age," he said. "But even though they may have embellished the view of the kingdom, that's not the same as saying it's not historical at all."

One reason archaeologists can't resolve their debate, he said, is that no one has yet found ancient scriptural texts written during the primary Old Testament era.

The earliest writing found so far, he said, is the Dead Sea Scrolls, which only date to about 250 years before the birth of Jesus.

One possible reason for that is that the area around the ancient capital of Jerusalem is wetter than other parts of the region, so texts written on papyrus or animal skins may have had a harder time surviving the ravages of time.

Another possibility is that the texts are out there, but archaeologists haven't found them yet.

Even though biblical digs in modern Israel, Jordan and Lebanon make that region "probably the most excavated piece of real estate on Earth," there is simply not enough money or expertise to check all the locations.

Dr. Tappy's team has been working at Tel Zayit since 1999 -- "tel" is Hebrew for "mound."

Although people who rubberneck at excavation sites may conclude that humans strip away land when they develop it, they actually build up the soil over a long period of time.

At some archaeological digs at Native American sites in the United States, Dr. Tappy said, those occupied layers may be very thin because the settlement lasted a relatively short period.

But in Palestine, the tels have many, many occupied layers.

The reason? "In the Middle East, people built their towns to be near some sort of trade route; they also deemed the site was defensible; and another very important factor was the availability of water. So they would choose a site that would incorporate as many of these variables as possible," he said.

"Then at some point they would be attacked and destroyed. And the conquerors or the survivors would typically go back to that very same spot, because the perennial spring that provides the water is right there."

As a working archaeologist, Dr. Tappy has seen his field change dramatically in recent years, both in the number of experts involved at digs and the technology they use.

Archaeologists didn't even think of using geologists to help them until the 1960s, he said. Since then, archaeological teams have also added experts on pottery, ancient economies, climate and anthropology, among other fields.

Measurements at sites are now done with laser beams for greater accuracy, he said, and archaeologists often use ground-penetrating radar and satellite photos to figure out the best places to dig.

Satellite photos are especially helpful in identifying ancient streambeds and roadways, he said.

And finally, there is the now ubiquitous computer, which is vital in creating the huge databases of information on all the items found at a site.

At Tel Zayit, he said, workers will unearth about 75,000 pottery fragments during a typical five-week dig.

"It's hard for me to believe how older archaeologists even did this work when they had to catalog items on index cards," he said.