 After five months he headed the mission station in the town of Gwalior, in what is now Madhya Pradesh .In September 1845, Pope Gregory XVI.made him the Vicar Apostolic of Patna and Titular Bishop of Derbe, with episcopal ordination at Akbar's Church on 15 March 1846 by the local Apostolic Vicar Alessandro Borghi (bishop), Hartmanns bishopric consisted of seven parishes that were supervised by four priests.