Many evangelicals view the fourth-century conversion of the Roman Emperor Constantine as an unfortunate chapter in church history, one that sabotaged the purity of the early church and ushered in the corrupt Middle Ages. Peter J. Leithart believes this version of church history is a myth. In Defending Constantine: The Twilight of an Empire and the Dawn of Christendom (IVP Academic), Leithart shows that the early church was not as united as we think, nor was Constantine the villain many have made him out to be.

Along the way, Leithart teases out contemporary implications regarding the church’s role in the world, implications that distance him from scholars like John Howard Yoder. Defending Constantine could have been called Dismantling Yoder, for although Leithart’s primary purpose is to vindicate Constantine, he devotes significant effort to pointing out the cracks in Yoder’s Anabaptist perspective on Christendom.

Defending Constantine begins as a biography. Leithart argues that the emperor was a sincere believer who transformed the empire by proclaiming “the end of sacrifice.” Citizens of Rome once expressed their support for the empire’s civic religion by making offerings to the city’s deities. In contrast, Constantine’s newfound Christianity insisted upon the once-for-all sacrifice of Jesus Christ.

Leithart does not portray Constantine as a power-hungry leader who adopted Christianity for political gain, as some have. Nor is he the saint (or apostle!) some ancient Christians thought him to be. Instead, we see a complex individual who gave preferential treatment to Christians without dominating church councils.

At times, Leithart’s sketch of Constantine is overly sympathetic, a portrayal challenged by the emperor’s hatred for the Jews and his murder of his wife and son. While Leithart notes these unflattering incidents, he is unable to find a place for them in his overall portrait that makes sense of the man.

The greatest strength of Leithart’s proposal comes later in the book, when he demonstrates how Anabaptist thinkers like Yoder oversimplify the issues surrounding Constantine’s reign. By showing, for example, that the early church was not universally pacifistic, Leithart casts doubt on Yoder’s insistence that the so-called uniform non-violence of the early church should be the norm today.

Interestingly enough, Leithart agrees with Yoder’s critique of Constantinianism: It is indeed a heresy that seeks efficiency instead of faithfulness to Christ. The difference is that Leithart does not believe we should name this heresy after Constantine. Instead, we should recognize the great debt we owe to Constantine for “desacrificing” Rome and thus allowing Christians to worship without fear of retribution.

Defending Constantine demonstrates the enduring relevance of the “Constantinian moment” of the fourth century. While recent scholarship has focused mainly on the negative results, Leithart swings the pendulum back, reminding us of all the good that God brought from this contested period of history.

(This review first appeared in the March 2011 issue of Christianity Today.)