As religious fundamentalism is seemingly on the rise across the globe, this four-part series is a timely reminder that it is no new thing. The Catholic Church’s institutional system of persecution, the Inquisition, ran for more than 500 years, from early in the 13th century to the 18th. We start with the Albigensian Crusade in 1209 against the reformist Cathars of southern France, which produced horrors such as the massacre at Béziers
in which 10,000 citizens were killed in a single day.

The programme almost revels in the gruesome details, with shadowy, blood-drenched reconstructions, and a historian who takes a gleeful delight in demonstrating instruments of torture.

Documentary telling the story of the bloody and menacing work of the Inquisition, established to combat heresy within the Catholic Church. The opening edition focuses on the persecution of the Knights Templar and the Cathars.