Medieval Treasury, Victoria & Albert Museum/Art Resource, N.Y.

This delicate ivory plaque, also carved 900 years ago, depicts Jesus seated on a cushioned throne. Like Buddha, Jesus raises his right hand in benediction.

In the accompanying article, Marcus Borg and Ray Riegert reflect on the lives of these two men who changed the world by creating two religions that are now home to so many. How were they alike? How did they differ? What common experiences shaped their thoughts, sayings and actions?