In the family conflict with Maurice, who fought with her over money, household goods and the education of the children, Juliane first defended her own interests and then those of her children, but without coming to a confrontation with her stepson, the ruling Landgrave William V. But she was also very active in the conflict within her own Nassau-Siegen family. She stood up for the Calvinists in the county of Nassau-Siegen who suffered from the recatholicisation attempts of her brother John VIII, who had converted to the Catholic Church and was in Spanish service.
