After Austria was defeated by Prussia in the Battle of Königgrätz in 1866 and after Franz Joseph I of Austria was crowned as Hungarian king in 1867, Kvaternik got amnesty from the Austrian Emperor and approval for his return. Ban Levin Rauch also gave him Austrian citizenship and permitted him to work as a lawyer. As of then, Kvaternik worked as a lawyer and also dealt with history. He published his book "Eastern Question and the Croats" in two volumes. Kvaternik was also involved in publishing activities; between 1868-70 he wrote for the magazine "Hrvat" ("The Croat"). In 1871 he was publishing an official newspaper of the "Party of Rights Hrvatska".