Final answer:
The Anabaptists were the Protestant Reformation group that practiced adult baptism and sought separation of church and state, leading to their persecution for refusals to pay taxes or serve in the military.
Step-by-step explanation:
The radicals and outcasts of the Protestant Reformation who believed in baptizing only true believers at an adult age, and who were known for their stance on the separation of church and state as well as their pacifism, are referred to as the Anabaptists. The Anabaptists also held the position of refusing to pay taxes or serve in the military, which led to them being persecuted by most European rulers. They were part of a broader religious upheaval during the Protestant Reformation that included various factions with differing beliefs on baptism, church governance, and the relationship between church and state.
Other Anabaptist groups included the Hutterites, the Mennonites, and the Amish, which emerged from a split in the Mennonite movement in the seventeenth century. The refusal of the Anabaptists to participate in secular government and their commitment to nonviolence often placed them at odds with authorities and made them targets of violence and oppression.