In the latter half of the 16th century, France was torn by a religious conflict between Catholics and Protestants, called Huguenots, which mainly referred to French Calvinists. Catherine de Medici, the mother of the young king Charles IX hit upon a plan to finally exterminate the Protestants; she proposed that a marriage should be arranged between Margaret, the catholic sister of King Charles, and Henry de Bourbon, the Huguenot king of Navarre. All the notable leaders of the land were invited to the wedding including Gaspard de Coligny the foremost Huguenot. The stage was for one of the most horrible crimes in recorded history: Saint Bartholomew's day Massacre. On August 24, 1572, Catherine went to her son with a fabricated story of a plot to assassinate the royal family and catholic leaders, bringing with her a document warranting the slaughter of all the Huguenots in Paris. The king initially refused to sign, but finally exclaimed, "I consent, but not one of the Huguenots must remain alive in France to reproach me with the deed." The Paris mob stormed the house of Coligny, killed him, cut off his head and sent it to Catherine and Charles. Then they dragged the body through the streets of Paris. The head was later embalmed and sent to the pope as a trophy. For three days Thousands of Huguenots including women and children were murdered in Paris. A decree went out to purge France of heretics. Massacres were carried out all over the country, with death toll estimates ranging wildly, from thousands to as high as 110,000. Regardless, an amnesty granted in 1573 pardoned the perpetrators. When news of the massacre reached the Vatican, there was rejoicing. Pope Gregory XIII actually had a commemorative medal struck to honor the occasion. The merciless slaughter remains one of the blackest spots in the history of the Roman Catholic Church.