Cosimo III de' Medici was the penultimate Grand Duke of Tuscany from 1670 to 1723. He was the elder son of the incumbent grand duke, Ferdinando. Cosimo's fifty- three-year long reign, the longest in Tuscan history, was marked by a series of ultra-reactionary laws, which regulated prostitution and banned May celebrations, and witnessed Tuscany's deterioration to previously unknown economic lows. He was succeeded by his elder surviving son, Gian Gastone, upon his death in 1723.He married Marguerite Louise d'Orléans, a cousin of Louis XIV. It was a marriage frought with tribulation, largely due to her homesickness.Marguerite Louise eventually abandoned Tuscany for the Convent of Montemarte. Together, they had 3 children: Ferdinando in 1663, Anna Maria Luisa, Electress Palatine, in 1667, and Gian Gastone, the last Medicean ruler of Tuscany, in 1671.