When her husband died, her 14-year-old son Eberhard III was still a minor and his uncle Louis Frederick, Duke of Württemberg-Montbéliard acted as regent. After Frederick Louis died on 26 January 1631, the regency was taken up by Sophie Barbara and Julius Frederick, Duke of Württemberg-Weiltingen, with Sophie Barbara being "high regent". She therefore moved back to Stuttgart in 1632 and became politically active. After the Battle of Lutzen in late 1632, Julius Frederick joined the war on the Swedish side. His goal was to drive enemy troops out of the country, as well as the Catholic former owners of secularized church properties. Despite his successes, he was accused of acting selfishly. The councillors and the Estates managed to drive him out of the regency.