You may be thinking, "How is a discussion of Christendom relevant to 21st century believers since the vast majority of Christians have never heard of it or know what it is?" Good point, but then many followers of Christ, if asked, couldn't tell you much about the doctrine of the
substitutionary atonement. Nevertheless that doctrine is essential to a correct understanding of the gospel. Most Christians never use the words
substitutionary atonement when giving their personal testimony, but they do affirm with great joy that Christ died in their place when they deserved to receive God's punishment. My point is that often the subtilty and depth of biblical teachings are frequently absent from the everyday conversation of Christians. Such is the case with Christendom. I think that Christians often believe in some vague notions akin to the concept of Christendom without having any substantial knowledge about it. I did for years.
On the other hand you may have heard about Christendom and even understand its role in church history, but still wonder whether this is a worthwhile discussion. For example you maybe asking the following questions or other like them.
Isn't Christendom dead? Why talk about something that's dead?
Isn't Christendom a Roman Catholic idea concocted during the Middle Ages?
Isn't the idea of Christendom contrary to biblical teaching on such topics as end times
apostasy, the individual nature of conversion, Christ's warnings about laying up treasures on earth, etc?
Isn't the idea of Christendom dangerous? Doesn't history show us how corrupt the church became once it became the official religion of Rome? Haven't we learned that the church and state need to be separate institutions for the sake of both?
I could go on. There are good answers to these very valid questions. On this site I hope to explore the meaning of Christendom for today and to address such questions along the way. That will take me down all sorts of roads, lead to some dead ends, and occasionally leave me out on a limb chainsawing my way to the forest floor.