One Sunday around 1173, in Lyons, a wealthy financier named Waldo heard a traveling singer tell the story of St. Alexis, the son of a Roman senator who fled his family, became a beggar, and took to a life of prayer and service. Moved, he hurried to talk to a theologian, who told him of Jesus’ exhortation: if you wish to be perfect, go, sell what you have, and give it to the poor. And so he did.

There’s a fable I often heard growing up, about a Mennonite man (or Amish or Brethren, depending on where the story is being told) who was asked whether he was a Christian. His response: “Ask my neighbors.” The story encapsulates a certain historicist impulse in the Anabaptist tradition: the commitments we claim matter less than the commitments we embody. I first learned to care about the history of my community for just that reason. We learn who we are by considering honestly how we have lived.

The Middle Ages were filled with strange, passionate, and fascinating figures, often hidden from our view by the long shadows of the likes of Anselm, Francis, Aquinas, or Ockham. The great theologians earned their influence, of course, but there are also things to learn from some of those to whom history has been less magnanimous. I want to introduce one such figure here: Arnold of Brescia.