The Gospel Coalition online has published the first of a new series on “big questions” and I found it interesting and enjoyable. What follows is a short discussion on some of the biggest moments in church history. Enjoy!

For the inaugural article in our new series “Big Questions,” The Gospel Coalition asked four Christian historians, “After AD 70, what day most changed the course of Christian history?”

Robert Louis Wilken is William R. Kenan professor emeritus of the history of Christianity at the University of Virginia. His most recent book is The First Thousand Years: A Global History of Christianity.

A good case can be made for the Muslim invasion of the Middle East in mid-seventh century, let us say AD 650.

No event during the first millennium was more unexpected, more calamitous, and more consequential for Christianity than the rise of Islam. Few irruptions in history have transformed societies so completely and irrevocably as did the conquest and expansion of the Arabs in the seventh century. And none came with greater swiftness. Within a decade three major cities in the Byzantine Christian Empire—Damascus in 635, Jerusalem in 638, and Alexandria in 641—fell to the invaders. Most of the territories that were Christian in the year 700 are now Muslim. Nothing similar has happened to Islam. Christianity seems like a rain shower that soaks the earth and then moves on, whereas Islam appears more like a great lake that constantly overflows its banks to inundate new territory.

George Marsden is professor emeritus in history at the University of Notre Dame and the author of Jonathan Edwards: A Life.

I think it has to be the day that Constantine was converted to Christianity. That had huge effects both for good and for ill ever after.

Philip Jenkins is the distinguished professor of history and co-director for the program on historical studies of religion for the Institute for Studies of Religion at Baylor University. He is the author of of The Lost History of Christianity: The Thousand-Year Golden Age of the Church in the Middle East, Africa, and Asia—and How It Died.

I would choose May 29, 1453, known throughout the Eastern churches as “the day the world ended.” Although the Byzantine Empire by that point was a pale shadow of its former self, it was still a ghostly shadow of the Roman Empire, and the seat of the Orthodox Church that once dwarfed the Catholics in power and prestige. On that day, though, the Roman capital of Constantinople fell to the Ottoman Turks, beginning a period of long centuries when most Eastern Christians would survive under the grudging tolerance of Islamic rule. The event may be symbolic, but it still marks a decisive turning point in Christian history.

Thomas S. Kidd is professor of history at Baylor University. He is writing a biography of George Whitefield and previously published The Great Awakening: The Roots of Evangelical Christianity in Colonial America.

On October 19, 1740, the First Great Awakening’s most compelling preacher, George Whitefield, spoke at the church of the Great Awakening’s most compelling theologian, Jonathan Edwards. This moment signaled the beginning of evangelicalism, the most dynamic movement in modern Christian history. Although Edwards and Whitefield did not always see eye-to-eye, they represented two aspects of evangelicalism at its best.

Edwards was the brilliant pastor of Northampton, Massachusetts, whose writings on doctrine and revival are some of the most rigorous the church has ever seen. Whitefield took the gospel to the ends of the earth (which, for this English itinerant, meant America), generating unprecedented excitement through impassioned oratory and skillful use of media. While Edwards represented the evangelical mind, and Whitefield embodied evangelical action, both still appreciated the other’s strength. Edwards itinerated, too, and oversaw two major revivals at his church, while Whitefield strongly promoted Calvinist doctrine and risked permanent schism with his Methodist ally John Wesley because of it.

Whitefield and Edwards seemed to sense the significance of the moment: the normally stoic Edwards wept through much of Whitefield’s sermon. Edwards thought the Whitefield’s revivals might herald “the dawning of a day of God’s might, power, and glorious grace.”