Professor Diarmaid MacCulloch continues his exploration of how Christianity has shaped western attitudes to sex, gender and sexuality through history. Travelling from the north east of England to Germany and Italy, he explains how the Christian Church took control of marriage in the 11th century, turning a civil institution into a sacred rite of Christianity. And he reveals how the Protestant Reformation launched a sexual revolution.

In this final episode of the series, professor Diarmaid MacCulloch explores how the offical Christian Church and Western society have moved apart on issues of sex and gender over the last 300 years. The Enlightenment encouraged people to question authority and that included the Church's teachings on sex. In the late 17th century, prostitution and homosexuality openly flourished in western cities - an open affront to centuries of Christian teaching. At the same time, new forms of Protestantism, such as Methodism, began to question traditional Church teaching, giving leadership roles to women.