Second in a five-part series in which Christopher Frayling investigates the art and philosophy of the Middle Ages.

As medieval society, still haunted by the terrible spectre of the Apocalypse and the day of judgment, struggled to cope with the changes overtaking it, religious dissidents paid a terrible price for their non-conformism. Francis of Assisi's belief in a life of poverty led him into conflict with an often extravagant Church, although he was eventually reconciled and established a monastic order under the auspices of Rome. But other dissidents were not so lucky. The Pope, alarmed at signs of disorder, called for a crackdown against heretics in the south of France. What followed proved to be one of the most brutal episodes in French history.

BBC Book: Christopher Frayling's Strange Landscape: A Journey through the Middle Ages is available price £18.99 from booksellers.