How did Christianity become one of the most widespread religions as well as one of the most influential forces in world history that has shaped politics, wars, literature, art, and music on every continent? This book contains more than 40 entries on various topics in early Christianity, 15 primary documents, and 6 argumentative essays written by scholars in the field. The breadth of materials enables readers to learn about early Christianity from a number of different viewpoints and to come to their own conclusions about how historical events unfolded in early Christianity. This single-volume work focuses on the first four centuries of early Christianity, including topics on Jerusalem, Herod the Great, Paul, Tertullian, Mani, The Arians, Constantine the Great, and many others. Readers will be well equipped to answer three critical questions that scholars of early Christianity deal with when they study this period: Why was Christianity popular? Why were Christians persecuted? How did Christianity spread?