"And they went along the Roman roads through Amphipolis and Apollonia."

                                                                                                                                                                        -Acts of the Apostles, 17:1

The very stones that created a thousand-year empire also helped destroy it.

Not long after the crucifixion of Jesus, the first Christians got into a shouting match over the nature of their faith. They lived in Jerusalem, the center of the Jewish world, and one faction felt that to be a follower of Christ still meant keeping kosher, just as their parents had. Others were just as convinced that believing in Jesus freed them from the religious code of their ancestors.

Frustrated that they couldn't get their point across at home, members of the latter group decided to, quite literally, take their side of the argument on the road. Led by St. Paul, they traveled from city to city through the eastern provinces of the Roman Empire, preaching their understanding of Jesus' life and mission. Along the way, those Apostles created the Christianity we know today: a faith rooted in the Old Testament but with its own set of beliefs and practices.

The imagery of Christmas could make you think that the birthplace of the Christian religion was some hick town tucked away in the sticks of the Old World. Shepherds come down from the hills to attend the infant Jesus, bringing their flocks right along with them. It's obvious the Wise Men from the East tower socially over the simple family with no better lodgings than a stable. Later in life, Jesus recruits his disciples from among semi-skilled tradesmen, like the fishermen James and John.

Yet in truth, Galilee, Bethlehem and the rest of Palestine were part of a Roman world whose technological underpinnings had reached a level by Jesus' day that was not to be surpassed until the 19th Century.

Those roads that St. Paul and his associates traveled to spread the faith were unprecedented marvels of engineering. Without the ingeniously constructed roads that led from the streets where Jesus had walked to the cities of Syria and Greece, Christianity might have remained another obscure Judean sect like those that fill the pages in accounts by Jewish historian Josephus.

Instead, by riding those Roman roads out of the Holy Land to become a faith for the wider world, Christianity was, in a very real sense, the first technologically driven religion.

Don't feel bad if you didn't realize the extent of the Romans' accomplishments or their role in the Christmas story. Schoolbooks are more likely to record the deeds of kings and queens than the achievements of surveyors and road builders. And in this present age of cyberspace marvels, it is hard to remember that not so long ago the ability to build a decent highway or provide a clean and reliable water supply marked the cutting edge of technology.

Indeed, the Romans themselves were resigned to being history's Rodney Dangerfield, unappreciated for setting the material stage upon which others more celebrated would perform. A near contemporary of Jesus, Sextus Julius Frontinus, wrote a book recounting his experience as Rome's water commissioner. It is filled with formulas for calculating the proper diameter of distribution pipes and helpful hints for preventing deposits from building up in the aqueducts, those huge constructions that gave the Romans potable water. Yet poor Frontinus was painfully aware that later generations would be tempted to lay aside his "Aqueducts of Rome" in favor of travel narratives from exotic Egypt or the plays of Sophocles and Euripides.

"With such an array of indispensable structures carrying so many waters, compare, if you will, the idle Pyramids or the useless, though famous, works of the Greeks," Frontius almost pleaded with readers.

Still, the Romans did take a quiet pride in having discovered a secret of statecraft unknown to their predecessors. Before them, empires were built with the sword, which usually gave them a short half-life. As soon as horsemen and foot soldiers had passed on, the newly conquered would be quick to revolt. The Romans realized that commerce is a more dependable glue of empire. So wherever their legions went, they laid down roads in all, 53,638 miles of main highway stretching from Palestine to England, from North Africa to Germany.

They weren't, of course, the first to build a road, the concept being self-evident. But the Romans do seem to have been early to realize that the real trick is to build one that will last. Absent that, washouts and potholes develop brigand's helpmates. Throughout ancient times, and well into the modern period, once the Romans were gone, highwaymen would station themselves at undependable stretches of road, waiting for their prey to break an axle or wind up in a ditch. By the time Christianity's missionaries were on the road, the orator Aristides was able to report that such impediments to trade and communication had largely vanished from the Roman Empire.

"Now any man can go whither he pleases with absolute confidence," boasted Aristides, "even the mountains are as safe for those who journey over them as the cities are to those who dwell in them."

The key to the Romans' success as road builders was simple, as technological breakthroughs often are. Rainwater is a highway's most deadly enemy. Working its way down between the paving blocks, it will eventually separate a road from the foundation it sits upon, undermining the roadway no matter how well constructed and the Romans built their roadbeds at least four layers deep and 26 feet wide. The secret, then, is to get rainwater off a highway as quickly as it falls. So Roman engineers built roads with a convex cross-section or camber, those curves designed to carry water off to the side, where it could be collected in gutters paralleling the highway.

Elegant solutions generally prove lasting ones: Take a look at the roadway outside your home. Engineers still employ the Roman method.

Those cities whose safety Aristides celebrated were settlements on a scale the world hadn't yet seen. Rome itself had a million residents in the age of Jesus. Antioch, where St. Paul preached on one of his first missionary voyages, was a city of 300,000. So, too, was Alexandria, where the Apostle Mark brought the news of Jesus' mission.

Indeed, Christianity skipped across the empire, moving so fast from city to city in the generations after the Apostles that it quickly became a quintessentially urban faith. "Pagan," Christianity's pejorative term for non-believer, derives from "paganus," Latin for country dweller.

For that many people to gather together in one location requires two material conditions: Some way to bring them a sufficient supply of water, and a parallel method of carrying off their wastes. Without the latter, city folks are easy prey to disease, which is exactly what happened once the Romans were gone, reducing the cities of the Middle Ages to a tiny fraction of the size of their ancient predecessors. Indeed, it wouldn't be until the 18th and 19th Centuries that Europe would again see urban settlements on the scale that the Christian missionaries did.

Roman plumbers were veritable artists whose medium was clay drainage tiles and lead pipes. In each of the Empire's principal cities, they constructed great public baths, something like a modern Turkish bath but capable of accommodating thousands of citizens in enormous sweating rooms heated by the passage of hot air through ducts in their walls and floors.

To fill those baths, as well as to supply citizens with water to drink and cook with, Roman engineers built those aqueducts of which Frontius was the proud commissioner. Some had enormous water-carrying capacities. According to a conservative modern estimate, Rome's aqueducts brought the capital 150 million to 200 million gallons a day or more water per capita than London was to enjoy until relatively recently.

Those numbers are even more impressive when you consider that the people of Christ's day lacked the modern sources of motive powersteam, hydrocarbon fuels and electricity. Water had to be moved from its source to a city by the force of gravity, which meant constructing aqueducts that sloped always and gently downhill. The most famous surviving aqueduct, the Pont du Gard near Nimes in southern France, rises 180 feet above a river valley, its water trough being carried atop three sets of arches.

Rome's surveyors and engineers also contributed to the rise of Christianity in a less concrete, more subtle way. Their very success at getting some measure of control over the physical environment turned many Romans into skeptics, quiet critics of their older religion with its pantheon of gods. Educated Romans of the imperial period tended to believe that there was nothing to believe in, that science could explain everything without recourse to supernatural beings.

Yet it seems to be a consistent facet of human nature that once our physical needs are met, we start wondering about larger questions, like the meaning of life. Recall how that happened in the Flower Children era, among the offspring of suburban American affluence.

Similarly, by the time Christ's disciples started traveling the Roman roads, many of their contemporaries were wondering if there wasn't more to our existence than those few years allotted us on this earth. Gravestones of the period attest to that longing. One such reads: "Here in my tomb I drain my cup more greedily because here I must sleep and here must stay forever."

So St. Paul and his successors found a ready audience when they preached to the citizens of the empire that life did not have to end at the grave. So ready, in fact, that within 200 years of Christ's death, his adherents were already well on their way to becoming the dominant religious community of the West. So noted the Christian theologian Tertullian, predicting that the days of the old Roman pagan cults were fast coming to an end.

"We are but of yesterday," Tertullian wrote, about 200 A.D., "and we have filled everything, cities, islands, camps, palace, forum--all you have left is the temples."

By Ron Grossman, Tribune Staff Writer.    Published: Monday, December 21, 1998