Jacques de Crussol, 2nd Duke of Uzès

Early in 1562 while his brother was working to ensure the south of France complied with the king's edicts, d'Acier accepted an offer from the Protestant church of Languedoc to be its military protector. In the civil war that broke out shortly thereafter he led a campaign of terror in Languedoc, becoming renowned for his cruel conduct. As military commander for the rebels of the region he oversaw the capture of Béziers and Marseillan.[1] His banner was emblazoned with a hydra representing Catholic cardinals being crushed by a Protestant Hercules.[5] His success would not last however and he would be bested by Joyeuse.[6] Stinging from the defeat he retreated to Montpellier Joyeuse attempted to besiege him however he prepared the city well, and was able to beat back his attempts, rebounding onto the offensive once more. He seized the town of Bourg-Saint-Andéol and massacred its garrison.[6] In November 1562 his brother Crussol was persuaded to assume the role of governor of Languedoc by the Protestants, he quickly installed Beaudiné as the lieutenant-general of the region.[7] D'Acier for his part was appointed lieutenant general and governor of Nîmes.[6]

In the peace that followed the civil war order was returned to Languedoc. Damville installed Catholic town councils across the region as its governor, ignoring the vehement protests of Crussol and d'Acier.[8] D'Acier was among the Protestant nobles who conspired to arrange the Surprise of Meaux with his role being to rise up in the south concurrently to the capture of the king and seize the towns of Languedoc.[9]

He oversaw the razing of the Cathedral in his families home town of Uzès so that the materials might be used to make it more defensible.[10] Then he travelled with his brother Beaudine to Nîmes, which had been seized in a coup shortly after Condé's attempt on the king, where he besieged the royal garrison that was holding out in the town and completed the coup.[11] The brothers then travelled to Montpellier, where despite rigorous defence by Joyeuse they were able to capture the city, d'Acier deciding to leave d'Aubais in charge of the city as he continued campaigning.[12]

While the second civil war had formerly been brought to a close with the Peace of Longjumeau campaigning continued in the south of France. D'Acier and Montbrun were brought to battle by Sommerive and defeated near Montfrin.[13] Safely in charge of Languedoc, Joyeuse re-instituted Catholicism in Uzès and other towns.[14]

Arriving at La Rochelle following his flight from court in late 1568, Condé put out the call for Protestant forces to be assembled and come to his aid. D'Acier responded to the call, mustering an army of many of the southern captains at Alais, around 20,000 strong to come to the prince's aid.[15] The crown was unable to prevent his forces achieving juncture with those of Condé on 1 November.[16] However part of his army under Mouvans separated from the main host and was crushed by the duke of Montpensier.[17]

The following year after the death of Condé at the Jarnac d'Acier's forces assisted in the withdrawal of the main body of the army under Coligny.[18] During the siege of Poitiers d'Acier was badly wounded. Shortly thereafter upon the death of Andelot, d'Acier was elevated to his position of Colonel-General of the infantry in the rebel army. [19] Fresh off his promotion he would fight with Coligny at the far more decisive engagement of the Battle of Moncontour where the rebel force was annihilated. Among the many leading Protestants captured, d'Acier was taken prisoner by the count Santa-Fiore.[20] He was saved from reprisals for his military conduct by the intervention of his brother, who secured his release.[5]

As the Massacre of Saint Bartholomew unfolded, d'Acier who had come to the capital for the wedding was protected by his wife and sister in law, both of whom were close to the court.[21]

In 1573 his brother Crussol died from an illness developed during the siege of La Rochelle, leaving the title of duc d'Uzès vacant. D'Acier quickly converted to Catholicism so that he could take advantage of the inheritance, becoming the second duc d'Uzès and a peer of France.[5][22] After the conclusion of the fourth civil war, d'Acier was charged in his role as Lieutenant-General of Languedoc to bring the Huguenots of the region back into obedience with the crown and the peace edict. He reported to the crown that there was a general dissatisfaction among the population with his attempts to administer justice.[23]

Allegiances were no longer so clearly delineated on religious grounds by 1574. The Malcontents (France), consisting of moderate Catholic and Protestant nobles conspired against the crown, however their plot was uncovered and civil war resumed. Damville, governor of Languedoc raised an army against the crown. He was opposed in his efforts to control Languedoc by the lieutenant general d'Acier, who now fought loyally for the crown.[24] The two sides fought a running campaign as they sought to achieve a decisive advantage, however neither commander was able to achieve a total victory.[25]

Henri III seeking religious advantage, and conscious of the dilution of the Order of Saint-Michel established a new order, that of the Order of the Holy Spirit, d'Acier was among those who first received the privilege.[26] In September 1586, d'Acier died.[27]