One of my great lights at Yale, the preeminent historical theologian Jaroslav Pelikan, in his Jesus Through the Centuries, wrote:

If a public opinion poll were to ask a representative group of informed and thoughtful people, “Which historical figure of the past two thousand years has most fully embodied the life and teaching of Jesus Christ?” the person mentioned most often would certainly be Francis of Assisi. That answer might, if anything, be even more frequent if the people polled were not affiliated with any church. And it is probably also the answer that many of his own contemporaries would have given to such a question — or at any rate, those who lived within a century or so after him. For in Francis of Assisi the imitation of the life of Jesus and the obedience to his teachings (which were, at least in principle, binding on every believer) attained such a level of fidelity as to earn for him the designation, eventually made official by Pope Pius XI, of “the second Christ [alter Christus].”