Why does the pope change his name?

What's in a pope's name?

By choosing the name Francis, the Argentine Jesuit who will lead the world's 1.2 billion Roman Catholics has signaled a devotion to simple living and social justice, analysts say.

No pope has ever chosen to be called Francis before, and it was not among the names favored by oddsmakers betting on which the new pontiff would choose. The name harks back to St. Francis of Assisi, who founded the Franciscan order.

Picking a name is the first decision made by the new pontiff and a closely watched sign of how he will lead the church....