In 1028, after Conrad's son Henry was crowned in Aachen as King of Germany, Gisela again intervened on Ernest's behalf. Conrad pardoned Ernest and released him from prison in 1028, but Gisela retained regency over Swabia. Ernest served as duke in name only. On Easter 1030, Conrad offered to restore Ernest his full powers as Duke of Swabia if he would crack down on the Emperor's enemies there. Ernest's refusal, especially against his friend Count Werner of Kyburg, resulted in his final downfall. Conrad stripped his stepson of his title, declared him a public enemy, and had him excommunicated. Even his mother Gisela did not come to his rescue. Within a few months, both Ernest and Werner, who had retreated to "Falkenstein Castle", south of modern Schramberg in the Black Forest were killed in a battle against a contingent of the Bishop of Constance. The fall of Ernest greatly weakened the sovereignty of Swabia. Conrad appointed Ernest's younger brother Herman as new Swabian prince. As Herman was still an infant, the Bishop of Constance was assigned his regent. Eight years later in 1038, Herman died and Conrad installed his own son Henry as duke, securing imperial control over the duchy.