Complex sentence: Saints Peter and Paul became the cathedral parish for the diocese in 1898, after Pope Leo XIII officially transferred the seat of the Diocese of Vincennes to Indianapolis on March 28,1898, Bishop Chatard proceeded with plans to raise funds for a new cathedral.
Split into simpler sentences: Saints Peter and Paul became the cathedral parish for the diocese on March 28,1898, when Pope Leo XIII officially transferred the seat of the Diocese of Vincennes to Indianapolis. At that time Bishop Chatard proceeded with his plans to raise funds for a new cathedral.