The assassination of Henry IV in 1610, and the advent of Louis XIII under the regency of Marie de' Medici, marked a return to pro-Catholic politics and a weakening of the position of the Protestants. The Duke Henri de Rohan and his brother Soubise started to organize Protestant resistance from that time, ultimately exploding into a Huguenot rebellion. In 1621, Louis XIII besieged and captured Saint-Jean d'Angély, and a Blockade of La Rochelle was attempted in 1621-1622, ending with a stalemate and the Treaty of Montpellier.