Roman Catholic Diocese of Graz-Seckau Tags: Clerical Administrative Region, Diocese.The Roman Catholic Diocese of Graz-Seckau (Latin: Dioecesis Seccoviensis German: Diözese Graz-Seckau) is a diocese comprising the Austrian state of Styria and is part of the Ecclesiastical province of Salzburg. thumbnail point area (km2) 1.6392e+10 country Austria Established June 22 1218 jurisdiction Diocese patron Vergilius of Salzburg, Saint Robert province Roman Catholic Archdiocese of Salzburg territory Styria latitude 47.0719 longitude 15.4422 Learn more... Loading...