Cardinal Francis George turns 75 on Monday, and that means he’ll be submitting his mandatory letter of resignation.

In the Roman Catholic Church, bishops are required to write a letter of resignation when they hit 75. The pope doesn’t have to accept it, however, so bishops often stay in office a few more years.

Cardinal George has said he doesn’t want to retire yet. He’s survived cancer, and says he feels good about his health.

Cardinals can serve as electors of the pope until they’re 80.

“We have never experienced this problem in Chicago, since all my predecessors died before they were 75,” Cardinal George said in a statement. “I am eager to be the first Archbishop of Chicago to retire!”

The cardinal’s known as a conservative bishop who’s spoken out against gay marriage and the ordination of women.

George gained national prominence as president of the U.S. Conference of Catholic Bishops, a post he held from 2007 to 2010.