<P> During the 1550s, Henry II became concerned about the threat of an English or Holy Roman Empire attack on Paris, and strengthened the defences of the Bastille in response . The southern gateway into the Bastille became the principal entrance to the castle in 1553, the other three gateways being closed . A bastion, a large earthwork projecting eastwards from the Bastille, was built to provide additional protective fire for the Bastille and the Arsenal; the bastion was reached from the fortress across a stone abutment using a connecting drawbridge that was installed in the Bastille's Comté tower . In 1573 the Porte Saint - Antoine was also altered--the drawbridges were replaced with a fixed bridge, and the medieval gatehouse was replaced with a triumphal arch . </P> <P> The Bastille was involved in the numerous wars of religion fought between Protestant and Catholic factions with support from foreign allies during the second half of the 16th century . Religious and political tensions in Paris initially exploded in the Day of the Barricades on 12 May 1588, when hard - line Catholics rose up in revolt against the relatively moderate Henry III . After a day's fighting had occurred across the capital, Henry III fled and the Bastille surrendered to Henry, the Duke of Guise and leader of the Catholic League, who appointed Bussy - Leclerc as his new captain . Henry III responded by having the Duke and his brother murdered later that year, whereupon Bussy - Leclerc used the Bastille as a base to mount a raid on the Parlement de Paris, arresting the president and other magistrates, whom he suspected of having royalist sympathies, and detaining them in the Bastille . They were not released until the intervention of Charles, the Duke of Mayenne, and the payment of substantial ransoms . Bussy - Leclerc remained in control of the Bastille until December 1592, when, following further political instability, he was forced to surrender the castle to Charles and flee the city . </P> <P> It took Henry IV several years to retake Paris . By the time he succeeded in 1594, the area around the Bastille formed the main stronghold for the Catholic League and their foreign allies, including Spanish and Flemish troops . The Bastille itself was controlled by a League captain called du Bourg . Henry entered Paris early on the morning of 23 March, through the Porte - Neuve rather than the Saint - Antoine and seized the capital, including the Arsenal complex that neighboured the Bastille . The Bastille was now an isolated League stronghold, with the remaining members of the League and their allies clustering around it for safety . After several days of tension, an agreement was finally reached for this rump element to leave safely, and on 27 March du Bourg surrendered the Bastille and left the city himself . </P> <P> The Bastille continued to be used as a prison and a royal fortress under both Henry IV and his son, Louis XIII . When Henry clamped down on a Spanish - backed plot among the senior French nobility in 1602, for example, he detained the ringleader Charles Gontaut, the Duke of Biron, in the Bastille, and had him executed in the courtyard . Louis XIII's chief minister, Cardinal Richelieu, is credited with beginning the modern transformation of the Bastille into a more formal organ of the French state, further increasing its structured use as a state prison . Richelieu broke with Henry IV's tradition of the Bastille's captain being a member of the French aristocracy, typically a Marshal of France such as François de Bassompierre, Charles d'Albert or Nicolas de L'Hospital, and instead appointed Père Joseph's brother to run the facility . The first surviving documentary records of prisoners at the Bastille also date from this period . </P>

When was the fort of bastille razed to ground