Catholics are reflecting on a historic moment at St. Patrick's Cathedral this Christmas Day. 

Timothy Cardinal Dolan is leading Christmas Mass for the final time as the Archdiocese of New York prepares for a change in leadership. 

Christmas at St. Patrick's Cathedral is always significant, but this year it marks the end of an era. Millions will watch Dolan's farewell. 

Dolan turned 75 this year, the age when Catholic bishops are required to submit their resignations. It brings to a close his 16 year run as archbishop of New York. 

Throughout Christmas morning, worshippers filled the cathedral, some flying in from across the world, hoping to be part of this historic moment in person. 

"It's just overwhelming with happiness, joy and spending Christmas with my family," Jamie Vejare said. "I'm really excited about it. I'm not from New York. It's my first time in New York. I had to be up at 5 a.m. to get her and beat the crowds. I'm so excited, I can't even explain it." 

Just days ago, Dolan formally introduced his successor, Bishop Ronald Hick of Joliet, Illinois, who will soon become the archbishop of New York. Bishop Hicks celebrated his final Midnight Mass in Joliet, streamed online.

"As I take the next steps, I take them with real love," Hicks said. 

At St. Pat's, the message on Christmas has been about faith, unity and tradition. 

"I'm sure he's going to do well here," Vejare said. 

The archdiocese says the transition to Bishop Hicks will happen in the coming months.