The Royal Collection is one of the most wide-ranging collections of art and artefacts in the world and provides an intriguing insight into the minds of the monarchs who assembled it. In this series, BBC Arts Editor Will Gompertz encounters dozens of these unique objects - some priceless, others no more than souvenirs - each shedding light on our relationship with the monarchy and giving a glimpse into the essential ingredients of a successful sovereign. A thousand years of monarchical history tell us that one crucial relationship for a monarch is with the church. In today's programme, Will sees how hard successive rulers have worked to make sure religion stayed on their side. It has not always been easy. The relationship with the church has through the centuries been so fraught as to threaten the survival of a sovereign. Will begins with an object used - only for a brief but crucial moment - in the coronation of the present Queen, then encounters an object that dates from the time of William the Conqueror and that has anointed some of England's most famous Kings and Queens in the eyes of God. He reads Henry VIII's robust defence of the Catholic faith, written just a few years before political expediency drove him to break with the Papacy; and sees a landscape painting that provides a possible insight into the private faith of Queen Victoria. Along the way, Will enlists the help of curators from the Royal Collection, Lord Indarjit Singh, historians Sir Diarmaid MacCulloch, Anna Whitelock and the Archbishop of Canterbury, Rowan Williams. Producer: Sarah Taylor.