During this exclusive interview, Father Gill calls for peace and unity during the Democratic National Convention in Philadelphia. The cathedral church (Cathedral Basilica of Saints Peter and Paul) is the principal church of the diocese, because it is here that the bishop as local ordinary of the diocese has his throne (chair), called the cathedra. Open since 1864 and located at the East side of Logan Square on 18th Street and the Benjamin Franklin Parkway, the cathedral is the mother church of the Archdiocese of Philadelphia. It is the largest brownstone structure in Philadelphia and the largest Catholic Church in Pennsylvania. The history of the Cathedral Basilica of Saints Peter and Paul is central to the history of the Archdiocese of Philadelphia.